The Colonial Origins of Comparative Development:
An Empirical Investigation
By DARON ACEMOGLU, SIMON JOHNSON, AND JAMES A. ROBINSON*
We exploit differences in European mortality rates to estimate the effect of institu-
tions on economic performance. Europeans adopted very different colonization
policies in different colonies, with different associated institutions. In places where
Europeans faced high mortality rates, they could not settle and were more likely to
set up extractive institutions. These institutions persisted to the present. Exploiting
differences in European mortality rates as an instrument for current institutions, we
estimate large effects of institutions on income per capita. Once the effect of
institutions is controlled for, countries in Africa or those closer to the equator do not
have lower incomes. (JEL O11, P16, P51)
What are the fundamental causes of the
large differences in income per capita across
countries? Although there is still little con-
sensus on the answer to this question, differ-
ences in institutions and property rights have
received considerable attention in recent
years. Countries with better “institutions,”
more secure property rights, and less distor-
tionary policies will invest more in physical
and human capital, and will use these factors
more efficiently to achieve a greater level of
income (e.g., Douglass C. North and Robert
P. Thomas, 1973; Eric L. Jones, 1981; North,
1981). This view receives some support from
cross-country correlations between measures
of property rights and economic development
(e.g., Stephen Knack and Philip Keefer, 1995;
Paulo Mauro, 1995; Robert E. Hall and
Charles I. Jones, 1999; Dani Rodrik, 1999),
and from a few micro studies that investigate
the relationship between property rights and
investment or output (e.g., Timothy Besley,
1995; Christopher Mazingo, 1999; Johnson et
al., 1999).
At some level it is obvious that institutions
matter. Witness, for example, the divergent
paths of North and South Korea, or East and
West Germany, where one part of the country
stagnated under central planning and collec-
tive ownership, while the other prospered
with private property and a market economy.
Nevertheless, we lack reliable estimates of
the effect of institutions on economic perfor-
mance. It is quite likely that rich economies
choose or can afford better institutions. Per-
haps more important, economies that are dif-
ferent for a variety of reasons will differ both
* Acemoglu: Department of Economics, E52-380b,
Massachusetts Institute of Technology, Cambridge, MA
02319, and Canadian Institute for Advanced Research
(e-mail: daron@mit.edu); Johnson: Sloan School of Man-
agement, Massachusetts Institute of Technology, Cam-
bridge, MA 02319 (e-mail: sjohnson@mit.edu); Robinson:
Department of Political Science and Department of Eco-
nomics, 210 Barrows Hall, University of California, Berke-
ley, CA 94720 (e-mail: jamesar@socrates.berkeley.edu).
We thank Joshua Angrist, Abhijit Banerjee, Esther Duflo,
Stan Engerman, John Gallup, Claudia Goldin, Robert
Hall, Chad Jones, Larry Katz, Richard Locke, Andrei
Shleifer, Ken Sokoloff, Judith Tendler, three anonymous
referees, and seminar participants at the University of
California-Berkeley, Brown University, Canadian Insti-
tute for Advanced Research, Columbia University, Har-
vard University, Massachusetts Institute of Technology,
National Bureau of Economic Research, Northwestern
University, New York University, Princeton University,
University of Rochester, Stanford University, Toulouse
University, University of California-Los Angeles, and the
World Bank for useful comments. We also thank Robert
McCaa for guiding us to the data on bishops’ mortality.
1369

in their institutions and in their income per
capita.
To estimate the impact of institutions on eco-
nomic performance, we need a source of exog-
enous variation in institutions. In this paper, we
propose a theory of institutional differences
among countries colonized by Europeans,1 and
exploit this theory to derive a possible source of
exogenous variation. Our theory rests on three
premises:
1. There were different types of colonization
policies which created different sets of insti-
tutions. At one extreme, European powers set
up “extractive states,” exemplified by the Bel-
gian colonization of the Congo. These institu-
tions did not introduce much protection for
private property, nor did they provide checks
and balances against government expropria-
tion. In fact, the main purpose of the extractive
state was to transfer as much of the resources
of the colony to the colonizer.
At the other extreme, many Europeans mi-
grated and settled in a number of colonies,
creating what the historian Alfred Crosby
(1986) calls “Neo-Europes.” The settlers tried
to replicate European institutions, with strong
emphasis on private property and checks
against government power. Primary examples
of this include Australia, New Zealand, Can-
ada, and the United States.
2. The colonization strategy was influenced by
the feasibility of settlements. In places where
the disease environment was not favorable to
European settlement, the cards were stacked
against the creation of Neo-Europes, and the
formation of the extractive state was more
likely.
3. The colonial state and institutions persisted
even after independence.
Based on these three premises, we use the
mortality rates expected by the first European
settlers in the colonies as an instrument for
current institutions in these countries.2 More
specifically, our theory can be schematically
summarized as
~potential! settler
mortality f settlements
f earlyinstitutions f
current
institutions
f currentperformance.
We use data on the mortality rates of soldiers,
bishops, and sailors stationed in the colonies be-
tween the seventeenth and nineteenth centuries,
largely based on the work of the historian Philip
D. Curtin. These give a good indication of the
mortality rates faced by settlers. Europeans were
well informed about these mortality rates at the
time, even though they did not know how to
control the diseases that caused these high mor-
tality rates.
Figure 1 plots the logarithm of GDP per
capita today against the logarithm of the settler
mortality rates per thousand for a sample of 75
countries (see below for data details). It shows a
strong negative relationship. Colonies where
Europeans faced higher mortality rates are to-
day substantially poorer than colonies that were
healthy for Europeans. Our theory is that this
relationship reflects the effect of settler mortal-
ity working through the institutions brought by
Europeans. To substantiate this, we regress cur-
rent performance on current institutions, and
instrument the latter by settler mortality rates.
Since our focus is on property rights and checks
against government power, we use the protec-
tion against “risk of expropriation” index from
Political Risk Services as a proxy for institu-
tions. This variable measures differences in in-
stitutions originating from different types of
states and state policies.3 There is a strong
1 By “colonial experience” we do not only mean the
direct control of the colonies by European powers, but more
generally, European influence on the rest of the world. So
according to this definition, Sub-Saharan Africa was
strongly affected by “colonialism” between the sixteenth
and nineteenth centuries because of the Atlantic slave trade.
2 Note that although only some countries were colonized,
there is no selection bias here. This is because the question
we are interested in is the effect of colonization policy
conditional on being colonized.
3 Government expropriation is not the only institutional
feature that matters. Our view is that there is a “cluster of
1370 THE AMERICAN ECONOMIC REVIEW DECEMBER 2001

(first-stage) relationship between settler mortal-
ity rates and current institutions, which is inter-
esting in its own right. The regression shows
that mortality rates faced by the settlers more
than 100 years ago explains over 25 percent
of the variation in current institutions.4 We also
document that this relationship works through
the channels we hypothesize: (potential) settler
mortality rates were a major determinant of
settlements; settlements were a major determi-
nant of early institutions (in practice, institu-
tions in 1900); and there is a strong correlation
between early institutions and institutions to-
day. Our two-stage least-squares estimate of the
effect of institutions on performance is rela-
tively precisely estimated and large. For ex-
ample, it implies that improving Nigeria’s
institutions to the level of Chile could, in the
long run, lead to as much as a 7-fold increase in
Nigeria’s income (in practice Chile is over 11
times as rich as Nigeria).
The exclusion restriction implied by our in-
strumental variable regression is that, condi-
tional on the controls included in the regression,
the mortality rates of European settlers more
than 100 years ago have no effect on GDP per
capita today, other than their effect through
institutional development. The major concern
with this exclusion restriction is that the mor-
tality rates of settlers could be correlated with
the current disease environment, which may
have a direct effect on economic performance.
In this case, our instrumental-variables esti-
mates may be assigning the effect of diseases on
income to institutions. We believe that this is
unlikely to be the case and that our exclusion
restriction is plausible. The great majority of
European deaths in the colonies were caused by
malaria and yellow fever. Although these dis-
eases were fatal to Europeans who had no im-
munity, they had limited effect on indigenous
adults who had developed various types of im-
munities. These diseases are therefore unlikely
to be the reason why many countries in Africa
and Asia are very poor today (see the discussion
in Section III, subsection A). This notion is
institutions,” including constraints on government expropri-
ation, independent judiciary, property rights enforcement,
and institutions providing equal access to education and
ensuring civil liberties, that are important to encourage
investment and growth. Expropriation risk is related to all
these institutional features. In Acemoglu et al. (2000), we
reported similar results with other institutions variables.
4 Differences in mortality rates are not the only, or even
the main, cause of variation in institutions. For our empir-
ical approach to work, all we need is that they are a source
of exogenous variation.
FIGURE 1. REDUCED-FORM RELATIONSHIP BETWEEN INCOME AND SETTLER MORTALITY
1371VOL. 91 NO. 5 ACEMOGLU ET AL.: THE COLONIAL ORIGINS OF DEVELOPMENT

supported by the mortality rates of local people
in these areas. For example, Curtin (1968 Table
2) reports that the annual mortality rates of local
troops serving with the British army in Bengal
and Madras were respectively 11 and 13 in
1,000. These numbers are quite comparable to,
in fact lower than, the annual mortality rates of
British troops serving in Britain, which were
approximately 15 in 1,000. In contrast, the mor-
tality rates of British troops serving in these
colonies were much higher because of their lack
of immunity. For example, mortality rates in
Bengal and Madras for British troops were be-
tween 70 and 170 in 1,000. The view that the
disease burden for indigenous adults was not
unusual in places like Africa or India is also
supported by the relatively high population den-
sities in these places before Europeans arrived
(Colin McEvedy and Richard Jones, 1975).
We document that our estimates of the effect
of institutions on performance are not driven by
outliers. For example, excluding Australia, New
Zealand, Canada, and the United States does not
change the results, nor does excluding Africa.
Interestingly, we show that once the effect of
institutions on economic performance is con-
trolled for, neither distance from the equator nor
the dummy for Africa is significant. These re-
sults suggest that Africa is poorer than the rest
of the world not because of pure geographic
or cultural factors, but because of worse
institutions.
The validity of our approach—i.e., our exclu-
sion restriction—is threatened if other factors
correlated with the estimates of settler mortality
affect income per capita. We adopt two strate-
gies to substantiate that our results are not
driven by omitted factors. First, we investigate
whether institutions have a comparable effect
on income once we control for a number of
variables potentially correlated with settler mor-
tality and economic outcomes. We find that
none of these overturn our results; the estimates
change remarkably little when we include con-
trols for the identity of the main colonizer, legal
origin, climate, religion, geography, natural re-
sources, soil quality, and measures of ethnolin-
guistic fragmentation. Furthermore, the results
are also robust to the inclusion of controls for
the current disease environment (e.g., the prev-
alence of malaria, life expectancy, and infant
mortality) and the current fraction of the popu-
lation of European descent.
Naturally, it is impossible to control for all
possible variables that might be correlated with
settler mortality and economic outcomes. Fur-
thermore, our empirical approach might capture
the effect of settler mortality on economic per-
formance, but working through other channels.
We deal with these problems by using a simple
overidentification test using measures of Euro-
pean migration to the colonies and early insti-
tutions as additional instruments. We then use
overidentification tests to detect whether settler
mortality has a direct effect on current perfor-
mance. The results are encouraging for our
approach; they generate no evidence for a direct
effect of settler mortality on economic
outcomes.
We are not aware of others who have pointed
out the link between settler mortality and insti-
tutions, though scholars such as William H.
McNeill (1976), Crosby (1986), and Jared M.
Diamond (1997) have discussed the influence of
diseases on human history. Diamond (1997), in
particular, emphasizes comparative develop-
ment, but his theory is based on the geograph-
ical determinants of the incidence of the
neolithic revolution. He ignores both the impor-
tance of institutions and the potential causes of
divergence in more recent development, which
are the main focus of our paper. Work by Ro-
nald E. Robinson and John Gallagher (1961),
Lewis H. Gann and Peter Duignan (1962),
Donald Denoon (1983), and Philip J. Cain and
Anthony G. Hopkins (1993) emphasizes that
settler colonies such as the United States and
New Zealand are different from other colonies,
and point out that these differences were impor-
tant for their economic success. Nevertheless,
this literature does not develop the link between
mortality, settlements, and institutions.
Our argument is most closely related to work
on the influence of colonial experience on insti-
tutions. Frederich A. von Hayek (1960) argued
that the British common law tradition was su-
perior to the French civil law, which was devel-
oped during the Napoleonic era to restrain
judges’ interference with state policies (see also
Seymour M. Lipset, 1994). More recently,
Rafael La Porta et al. (1998, 1999) emphasize
the importance of colonial origin (the identity of
1372 THE AMERICAN ECONOMIC REVIEW DECEMBER 2001

the colonizer) and legal origin on current insti-
tutions, and show that the common-law coun-
tries and former British colonies have better
property rights and more developed financial
markets. Similarly, David Landes (1998 Chap-
ters 19 and 20) and North et al. (1998) argue
that former British colonies prospered relative
to former French, Spanish, and Portuguese col-
onies because of the good economic and polit-
ical institutions and culture they inherited from
Britain. In contrast to this approach which
focuses on the identity of the colonizer, we
emphasize the conditions in the colonies. Spe-
cifically, in our theory—and in the data—it is
not the identity of the colonizer or legal origin
that matters, but whether European colonialists
could safely settle in a particular location:
where they could not settle, they created worse
institutions. In this respect, our argument is
closely related to that of Stanley L. Engerman
and Kenneth L. Sokoloff (1997) who also em-
phasize institutions, but link them to factor en-
dowments and inequality.
Empirically, our work is related to a number
of other attempts to uncover the link between
institutions and development, as well as to
Graziella Bertocchi and Fabio Canova (1996)
and Robin M. Grier (1999), who investigate the
effect of being a colony on postwar growth.
Two papers deal with the endogeneity of in-
stitutions by using an instrumental variables
approach as we do here. Mauro (1995) instru-
ments for corruption using ethnolinguistic frag-
mentation. Hall and Jones (1999), in turn, use
distance from the equator as an instrument for
social infrastructure because, they argue, lati-
tude is correlated with “Western influence,”
which leads to good institutions. The theoretical
reasoning for these instruments is not entirely
convincing. It is not easy to argue that the
Belgian influence in the Congo, or Western
influence in the Gold Coast during the era of
slavery promoted good institutions. Ethnolin-
guistic fragmentation, on the other hand, seems
endogenous, especially since such fragmenta-
tion almost completely disappeared in Europe
during the era of growth when a centralized
state and market emerged (see, e.g., Eugen
J. Weber, 1976; Benedict Anderson, 1983).
Econometrically, the problem with both studies
is that their instruments can plausibly have a
direct effect on performance. For example, Wil-
liiam Easterly and Ross Levine (1997) argue
that ethnolinguistic fragmentation can affect
performance by creating political instability,
while Charles de Montesquieu [1748] (1989)
and more recently David E. Bloom and Jeffrey
D. Sachs (1998) and John Gallup et al. (1998)
argue for a direct effect of climate on perfor-
mance. If, indeed, these variables have a direct
effect, they are invalid instruments and do not
establish that it is institutions that matter. The
advantage of our approach is that conditional on
the variables we already control for, settler mor-
tality more than 100 years ago should have no
effect on output today, other than through its
effect on institutions. Interestingly, our results
show that distance from the equator does not
have an independent effect on economic perfor-
mance, validating the use of this variable as an
instrument in the work by Hall and Jones
(1999).
The next section outlines our hypothesis and
provides supporting historical evidence. Section
II presents OLS regressions of GDP per capita
on our index of institutions. Section III de-
scribes our key instrument for institutions, the
mortality rates faced by potential settlers at the
time of colonization. Section IV presents our
main results. Section V investigates the robust-
ness of our results, and Section VI concludes.
I. The Hypothesis and Historical Background
We hypothesize that settler mortality affected
settlements; settlements affected early institu-
tions; and early institutions persisted and
formed the basis of current institutions. In this
section, we discuss and substantiate this hypoth-
esis. The next subsection discusses the link be-
tween mortality rates of settlers and settlement
decisions, then we discuss differences in colo-
nization policies, and finally, we turn to the
causes of institutional persistence.
A. Mortality and Settlements
There is little doubt that mortality rates were
a key determinant of European settlements.
Curtin (1964, 1998) documents how both the
British and French press informed the public of
mortality rates in the colonies. Curtin (1964)
1373VOL. 91 NO. 5 ACEMOGLU ET AL.: THE COLONIAL ORIGINS OF DEVELOPMENT

also documents how early British expectations
for settlement in West Africa were dashed by
very high mortality among early settlers, about
half of whom could be expected to die in the
first year. In the “Province of Freedom” (Sierra
Leone), European mortality in the first year was
46 percent, in Bulama (April 1792–April 1793)
there was 61-percent mortality among Europe-
ans. In the first year of the Sierra Leone Com-
pany (1792–1793), 72 percent of the European
settlers died. On Mungo Park’s Second Expedi-
tion (May–November 1805), 87 percent of Eu-
ropeans died during the overland trip from
Gambia to the Niger, and all the Europeans died
before completing the expedition.
An interesting example of the awareness of
the disease environment comes from the Pil-
grim fathers. They decided to migrate to the
United States rather than Guyana because of the
high mortality rates in Guyana (see Crosby,
1986 pp. 143–44). Another example comes
from the Beauchamp Committee in 1795, set up
to decide where to send British convicts who
had previously been sent to the United States.
One of the leading proposals was the island of
Lemane, up the Gambia River. The committee
rejected this possibility because they decided
mortality rates would be too high even for the
convicts. Southwest Africa was also rejected for
health reasons. The final decision was to send
convicts to Australia.
The eventual expansion of many of the col-
onies was also related to the living conditions
there. In places where the early settlers faced
high mortality rates, there would be less incen-
tive for new settlers to come.5
B. Types of Colonization and Settlements
The historical evidence supports both the no-
tion that there was a wide range of different
types of colonization and that the presence or
absence of European settlers was a key deter-
minant of the form colonialism took. Historians,
including Robinson and Gallagher (1961), Gann
and Duignan (1962), Denoon (1983), and Cain
and Hopkins (1993), have documented the de-
velopment of “settler colonies,” where Europe-
ans settled in large numbers, and life was
modeled after the home country. Denoon (1983)
emphasizes that settler colonies had representa-
tive institutions which promoted what the set-
tlers wanted and that what they wanted was
freedom and the ability to get rich by engaging
in trade. He argues that “there was undeniably
something capitalist in the structure of these
colonies. Private ownership of land and live-
stock was well established very early ...” (p.
35).
When the establishment of European-like in-
stitutions did not arise naturally, the settlers
were ready to fight for them against the wishes
of the home country. Australia is an interesting
example here. Most of the early settlers in Aus-
tralia were ex-convicts, but the land was owned
largely by ex-jailors, and there was no legal
protection against the arbitrary power of land-
owners. The settlers wanted institutions and po-
litical rights like those prevailing in England at
the time. They demanded jury trials, freedom
from arbitrary arrest, and electoral representa-
tion. Although the British government resisted
at first, the settlers argued that they were British
and deserved the same rights as in the home
country (see Robert Hughes, 1987). Cain and
Hopkins write (1993 p. 237) “from the late
1840s the British bowed to local pressures and,
in line with observed constitutional changes
taking place in Britain herself, accepted the idea
that, in mature colonies, governors should in
future form ministries from the majority ele-
ments in elected legislatures.” They also sug-
gest that “the enormous boom in public
investment after 1870 [in New Zealand] ... was
an attempt to build up an infrastructure ... to
maintain high living standards in a country
where voters expected politicians actively to
promote their economic welfare.” (p. 225).6
5 Naturally, other factors also influenced settlements. For
example, despite the relatively high mortality rates, many
Europeans migrated to the Caribbean because of the very
high incomes there at the time (see, e.g., Richard S. Dunn,
1972; David W. Galenson, 1996; Engerman and Sokoloff,
1997; David Eltis, 2000).
6 Robert H. Bates (1983 Chapter 3) gives a nice example
of the influence of settlers on policy in Africa. The British
colonial government pursued many policies that depressed
the price of cocoa, the main produce of the farmers in
Ghana. In contrast, the British government supported the
prices faced by the commercial cereal farmers in Kenya.
1374 THE AMERICAN ECONOMIC REVIEW DECEMBER 2001

This is in sharp contrast to the colonial expe-
rience in Latin America during the seventeenth
and eighteenth centuries, and in Asia and Africa
during the nineteenth and early twentieth cen-
turies. The main objective of the Spanish and
the Portuguese colonization was to obtain gold
and other valuables from America. Soon after
the conquest, the Spanish crown granted rights
to land and labor (the encomienda) and set up a
complex mercantilist system of monopolies and
trade regulations to extract resources from the
colonies.7
Europeans developed the slave trade in Af-
rica for similar reasons. Before the mid-nine-
teenth century, colonial powers were mostly
restricted to the African coast and concentrated
on monopolizing trade in slaves, gold, and other
valuable commodities—witness the names used
to describe West African countries: the Gold
Coast, the Ivory Coast. Thereafter, colonial pol-
icy was driven in part by an element of super-
power rivalry, but mostly by economic motives.
Michael Crowder (1968 p. 50), for example,
notes “it is significant that Britain’s largest col-
ony on the West Coast [Nigeria] should have
been the one where her traders were most active
and bears out the contention that, for Britain
... flag followed trade.”8 Lance E. Davis and
Robert A. Huttenback (1987 p. 307) conclude
that “the colonial Empire provides strong evi-
dence for the belief that government was at-
tuned to the interests of business and willing to
divert resources to ends that the business com-
munity would have found profitable.” They find
that before 1885 investment in the British em-
pire had a return 25 percent higher than that on
domestic investment, though afterwards the two
converged. Andrew Roberts (1976 p. 193)
writes: “[from] ... 1930 to 1940 Britain had kept
for itself 2,400,000 pounds in taxes from the
Copperbelt, while Northern Rhodesia received
from Britain only 136,000 pounds in grants
for development.” Similarly, Patrick Manning
(1982) estimates that between 1905 and 1914,
50 percent of GDP in Dahomey was extracted
by the French, and Crawford Young (1994 p.
125) notes that tax rates in Tunisia were four
times as high as in France.
Probably the most extreme case of extraction
was that of King Leopold of Belgium in the
Congo. Gann and Duignan (1979 p. 30) argue
that following the example of the Dutch in
Indonesia, Leopold’s philosophy was that “the
colonies should be exploited, not by the opera-
tion of a market economy, but by state interven-
tion and compulsory cultivation of cash crops to
be sold to and distributed by the state at con-
trolled prices.” Jean-Philippe Peemans (1975)
calculates that tax rates on Africans in the
Congo approached 60 percent of their income
during the 1920’s and 1930’s. Bogumil Jew-
siewicki (1983) writes that during the period
when Leopold was directly in charge, policy
was “based on the violent exploitation of natural
and human resources,” with a consequent “de-
struction of economic and social life ... [and]
... dismemberment of political structures.”
Overall, there were few constraints on state
power in the nonsettler colonies. The colonial
powers set up authoritarian and absolutist states
with the purpose of solidifying their control and
facilitating the extraction of resources. Young
(1994 p. 101) quotes a French official in Africa:
“the European commandant is not posted to
observe nature, ... He has a mission ... to impose
regulations, to limit individual liberties ... , to
collect taxes.” Manning (1988 p. 84) summa-
rizes this as: “In Europe the theories of repre-
sentative democracy won out over the theorists
of absolutism ... . But in Africa, the European
conquerors set up absolutist governments, based
on reasoning similar to that of Louis XIV.”
Bates shows that this was mainly because in Kenya, but not
in Ghana, there were a significant number of European
settler farmers, who exerted considerable pressure on
policy.
7 See James Lang (1975) and James Lockhart and
Stuart B. Schwartz (1983). Migration to Spanish America
was limited by the Spanish Crown, in part because of a
desire to keep control of the colonists and limit their
independence (see, for example, John H. Coatsworth,
1982). This also gives further support to our notion that
settlers were able to influence the type of institutions set
up in the colonies, even against the wishes of the home
country government.
8 Although in almost all cases the main objective of
colonial policies was to protect economic interests and
obtain profits, the recipients of these profits varied. In the
Portuguese case, it was the state; in the Belgian case, it was
King Leopold; and in the British case, it was often private
enterprises who obtained concessions or monopoly trading
rights in Africa (Crowder, 1968 Part III).
1375VOL. 91 NO. 5 ACEMOGLU ET AL.: THE COLONIAL ORIGINS OF DEVELOPMENT

C. Institutional Persistence
There is a variety of historical evidence, as well
as our regressions in Table 3 below, suggesting
that the control structures set up in the nonsettler
colonies during the colonial era persisted, while
there is little doubt that the institutions of law and
order and private property established during the
early phases of colonialism in Australia, Canada,
New Zealand, the United States, Hong Kong, and
Singapore have formed the basis of the current-
day institutions of these countries.9
Young emphasizes that the extractive institu-
tions set up by the colonialists persisted long
after the colonial regime ended. He writes “al-
though we commonly described the indepen-
dent polities as ‘new states,’ in reality they were
successors to the colonial regime, inheriting its
structures, its quotidian routines and practices,
and its more hidden normative theories of gov-
ernance” (1994 p. 283). An example of the
persistence of extractive state institutions into
the independence era is provided by the persis-
tence of the most prominent extractive policies.
In Latin America, the full panoply of monopo-
lies and regulations, which had been created by
Spain, remained intact after independence, for
most of the nineteenth century. Forced labor
policies persisted and were even intensified or
reintroduced with the expansion of export agri-
culture in the latter part of the nineteenth cen-
tury. Slavery persisted in Brazil until 1886, and
during the sisal boom in Mexico, forced labor
was reintroduced and persisted up to the start of
the revolution in 1910. Forced labor was also
reintroduced in Guatemala and El Salvador to
provide labor for coffee growing. In the Guate-
malan case, forced labor lasted until the creation
of democracy in 1945. Similarly, forced labor
was reinstated in many independent African
countries, for example, by Mobutu in Zaire.
There are a number of economic mechanisms
that will lead to institutional persistence of this
type. Here, we discuss three possibilities.
(1) Setting up institutions that place restrictions
on government power and enforce property
rights is costly (see, e.g., Acemoglu and
Thierry Verdier, 1998). If the costs of cre-
ating these institutions have been sunk by
the colonial powers, then it may not pay the
elites at independence to switch to extrac-
tive institutions. In contrast, when the new
elites inherit extractive institutions, they
may not want to incur the costs of introduc-
ing better institutions, and may instead
prefer to exploit the existing extractive in-
stitutions for their own benefits.
(2) The gains to an extractive strategy may
depend on the size of the ruling elite. When
this elite is small, each member would have
a larger share of the revenues, so the elite
may have a greater incentive to be extrac-
tive. In many cases where European powers
set up authoritarian institutions, they dele-
gated the day-to-day running of the state to
a small domestic elite. This narrow group
often was the one to control the state
after independence and favored extractive
institutions.10
(3) If agents make irreversible investments that
are complementary to a particular set of
institutions, they will be more willing to
support them, making these institutions per-
sist (see, e.g., Acemoglu, 1995). For exam-
ple, agents who have invested in human and
physical capital will be in favor of spending
9 The thesis that institutions persist for a long time goes
back at least to Karl A. Wittfogel (1957), who argued that the
control structures set up by the large “hydraulic” empires such
as China, Russia, and the Ottoman Empire persisted for more
than 500 years to the twentieth century. Engerman and
Sokoloff (1997), La Porta et al. (1998, 1999), North et al.
(1998), and Coatsworth (1999) also argue that colonial insti-
tutions persisted. Engerman et al. (1998) provide further evi-
dence supporting this view.
10 William Reno (1995), for example, argues that the
governments of postindependence Sierra Leone adopted the
tactics and institutions of the British colonizers to cement
their political power and extract resources from the rest of
society. Catherine Boone (1992) provides a similar analysis
of the evolution of the modern state in Senegal. Most
scholars also view the roots of authoritarianism under
Mobutu in the colonial state practices in the Belgian Congo
(e.g., Thomas M. Callaghy, 1984, or Thomas Turner and
Young, 1985, especially p. 43). The situation in Latin
America is similar. Independence of most Latin American
countries came in the early nineteenth century as domestic
elites took advantage of the invasion of Spain by Napoleon
to capture the control of the state. But, the only thing that
changed was the identity of the recipients of the rents (see,
for example, Coatsworth, 1978, or John Lynch, 1986).
1376 THE AMERICAN ECONOMIC REVIEW DECEMBER 2001

money to enforce property rights, while
those who have less to lose may not be.
II. Institutions and Performance:
OLS Estimates
A. Data and Descriptive Statistics
Table 1 provides descriptive statistics for the
key variables of interest. The first column is for
the whole world, and column (2) is for our base
sample, limited to the 64 countries that were
ex-colonies and for which we have settler mor-
tality, protection against expropriation risk, and
GDP data (this is smaller than the sample in
Figure 1). The GDP per capita in 1995 is PPP
adjusted (a more detailed discussion of all data
sources is provided in Appendix Table A1).
Income (GDP) per capita will be our measure of
economic outcome. There are large differences
in income per capita in both the world sample
and our basic sample, and the standard devia-
tion of log income per capita in both cases is
1.1. In row 3, we also give output per worker in
1988 from Hall and Jones (1999) as an alterna-
tive measure of income today. Hall and Jones
(1999) prefer this measure since it explicitly
refers to worker productivity. On the other
hand, given the difficulty of measuring the for-
mal labor force, it may be a more noisy measure
of economic performance than income per
capita.
We use a variety of variables to capture in-
stitutional differences. Our main variable, re-
ported in the second row, is an index of
protection against expropriation. These data are
from Political Risk Services (see, e.g., William
D. Coplin et al., 1991), and were first used in the
economics and political science literatures by
Knack and Keefer (1995). Political Risk Ser-
vices reports a value between 0 and 10 for each
country and year, with 0 corresponding to the
TABLE 1—DESCRIPTIVE STATISTICS
Whole world Base sample
By quartiles of mortality
(1) (2) (3) (4)
Log GDP per capita (PPP) in 1995 8.3 8.05 8.9 8.4 7.73 7.2
(1.1) (1.1)
Log output per worker in 1988 21.70 21.93 21.03 21.46 22.20 23.03
(with level of United States
normalized to 1)
(1.1) (1.0)
Average protection against 7 6.5 7.9 6.5 6 5.9
expropriation risk, 1985–1995 (1.8) (1.5)
Constraint on executive in 1990 3.6 4 5.3 5.1 3.3 2.3
(2.3) (2.3)
Constraint on executive in 1900 1.9 2.3 3.7 3.4 1.1 1
(1.8) (2.1)
Constraint on executive in first year 3.6 3.3 4.8 2.4 3.1 3.4
of independence (2.4) (2.4)
Democracy in 1900 1.1 1.6 3.9 2.8 0.19 0
(2.6) (3.0)
European settlements in 1900 0.31 0.16 0.32 0.26 0.08 0.005
(0.4) (0.3)
Log European settler mortality n.a. 4.7 3.0 4.3 4.9 6.3
(1.1)
Number of observations 163 64 14 18 17 15
Notes: Standard deviations are in parentheses. Mortality is potential settler mortality, measured in terms of deaths per annum
per 1,000 “mean strength” (raw mortality numbers are adjusted to what they would be if a force of 1,000 living people were
kept in place for a whole year, e.g., it is possible for this number to exceed 1,000 in episodes of extreme mortality as those
who die are replaced with new arrivals). Sources and methods for mortality are described in Section III, subsection B, and
in the unpublished Appendix (available from the authors; or see Acemoglu et al., 2000). Quartiles of mortality are for our base
sample of 64 observations. These are: (1) less than 65.4; (2) greater than or equal to 65.4 and less than 78.1; (3) greater than
or equal to 78.1 and less than 280; (4) greater than or equal to 280. The number of observations differs by variable; see
Appendix Table A1 for details.
1377VOL. 91 NO. 5 ACEMOGLU ET AL.: THE COLONIAL ORIGINS OF DEVELOPMENT

lowest protection against expropriation. We use
the average value for each country between
1985 and 1995 (values are missing for many
countries before 1985). This measure is appro-
priate for our purposes since the focus here is on
differences in institutions originating from dif-
ferent types of states and state policies. We
expect our notion of extractive state to corre-
spond to a low value of this index, while the
tradition of rule of law and well-enforced prop-
erty rights should correspond to high values.11
The next row gives an alternative measure, con-
straints on the executive in 1990, coded from
the Polity III data set of Ted Robert Gurr and
associates (an update of Gurr, 1997). Results
using the constraints on the executive and other
measures are reported in Acemoglu et al. (2000)
and are not repeated here.
The next three rows give measures of early
institutions from the same Gurr data set. The
first is a measure of constraints on the executive
in 1900 and the second is an index of democ-
racy in 1900. This information is not available
for countries that were still colonies in 1900, so
we assign these countries the lowest possible
score. In the following row, we report the mean
and standard deviation of constraints on the
executive in the first year of independence (i.e.,
the first year a country enters the Gurr data set)
as an alternative measure of institutions. The
second-to-last row gives the fraction of the pop-
ulation of European descent in 1900, which is
our measure of European settlement in the col-
onies, constructed from McEvedy and Jones
(1975) and Curtin et al. (1995). The final row
gives the logarithm of the baseline settler mor-
tality estimates; the raw data are in Appendix
Table A2.
The remaining columns give descriptive sta-
tistics for groups of countries at different quar-
tiles of the settler mortality distribution. This is
useful since settler mortality is our instrument
for institutions (this variable is described in
more detail in the next section).
B. Ordinary Least-Squares Regressions
Table 2 reports ordinary least-squares (OLS)
regressions of log per capita income on the
protection against expropriation variable in a
variety of samples. The linear regressions are
for the equation
(1) log yi 5 m 1 aRi 1 X9ig 1 «i ,
where yi is income per capita in country i, Ri is
the protection against expropriation measure, Xi
is a vector of other covariates, and «i is a
random error term. The coefficient of interest
throughout the paper is a, the effect of institu-
tions on income per capita.
Column (1) shows that in the whole world
sample there is a strong correlation between our
measure of institutions and income per capita.
Column (2) shows that the impact of the insti-
tutions variable on income per capita in our base
sample is quite similar to that in the whole
world, and Figure 2 shows this relationship di-
agrammatically for our base sample consisting
of 64 countries. The R2 of the regression in
column (1) indicates that over 50 percent of the
variation in income per capita is associated with
variation in this index of institutions. To get a
sense of the magnitude of the effect of institu-
tions on performance, let us compare two coun-
tries, Nigeria, which has approximately the 25th
percentile of the institutional measure in this
sample, 5.6, and Chile, which has approxi-
mately the 75th percentile of the institutions
index, 7.8. The estimate in column (1), 0.52,
indicates that there should be on average a 1.14-
log-point difference between the log GDPs of
the corresponding countries (or approximately a
2-fold difference—e1.14 2 1 ’ 2.1). In prac-
tice, this GDP gap is 253 log points (approxi-
mately 11-fold). Therefore, if the effect
estimated in Table 2 were causal, it would im-
ply a fairly large effect of institutions on per-
formance, but still much less than the actual
income gap between Nigeria and Chile.
Many social scientists, including Monte-
squieu [1784] (1989), Diamond (1997), and
11 The protection against expropriation variable is spe-
cifically for foreign investment, since Political and Risk
Services construct these data for foreign investors. How-
ever, as noted by Knack and Keefer (1995), risk of expro-
priation of foreign and domestic investments are very highly
correlated, and risk of expropriation of foreign investment
may be more comparable across countries. In any case, all
our results hold also with a variety of other measures of
institutions (see Tables 4a, b, c, d, and e in Acemoglu et al.,
2000, available from the authors).
1378 THE AMERICAN ECONOMIC REVIEW DECEMBER 2001

Sachs and coauthors, have argued for a direct
effect of climate on performance, and Gallup et
al. (1998) and Hall and Jones (1999) document
the correlation between distance from the equa-
tor and economic performance. To control for
this, in columns (3)–(6), we add latitude as a
regressor (we follow the literature in using the
absolute value measure of latitude, i.e., distance
from the equator, scaled between 0 and 1). This
changes the coefficient of the index of institu-
tions little. Latitude itself is also significant and
has the sign found by the previous studies. In
columns (4) and (6), we also add dummies for
Africa, Asia, and other continents, with Amer-
ica as the omitted group. Although protection
against expropriation risk remains significant,
the continent dummies are also statistically and
quantitatively significant. The Africa dummy in
column (6) indicates that in our sample African
countries are 90 log points (approximately 145
percent) poorer even after taking the effect of
institutions into account. Finally, in columns (7)
and (8), we repeat our basic regressions using
the log of output per worker from Hall and
Jones (1999), with very similar results.
Overall, the results in Table 2 show a strong
correlation between institutions and economic
performance. Nevertheless, there are a number
of important reasons for not interpreting this
relationship as causal. First, rich economies
may be able to afford, or perhaps prefer, better
institutions. Arguably more important than this
reverse causality problem, there are many omit-
ted determinants of income differences that will
naturally be correlated with institutions. Finally,
the measures of institutions are constructed ex
post, and the analysts may have had a natural
bias in seeing better institutions in richer places.
As well as these problems introducing positive
bias in the OLS estimates, the fact that the
institutions variable is measured with consider-
able error and corresponds poorly to the “cluster
of institutions” that matter in practice creates
attenuation and may bias the OLS estimates
TABLE 2—OLS REGRESSIONS
Whole
world
(1)
Base
sample
(2)
Whole
world
(3)
Whole
world
(4)
Base
sample
(5)
Base
sample
(6)
Whole
world
(7)
Base
sample
(8)
Dependent variable is log GDP per capita in 1995
Dependent variable
is log output per
worker in 1988
Average protection 0.54 0.52 0.47 0.43 0.47 0.41 0.45 0.46
against expropriation
risk, 1985–1995
(0.04) (0.06) (0.06) (0.05) (0.06) (0.06) (0.04) (0.06)
Latitude 0.89 0.37 1.60 0.92
(0.49) (0.51) (0.70) (0.63)
Asia dummy 20.62 20.60
(0.19) (0.23)
Africa dummy 21.00 20.90
(0.15) (0.17)
“Other” continent dummy 20.25 20.04
(0.20) (0.32)
R2 0.62 0.54 0.63 0.73 0.56 0.69 0.55 0.49
Number of observations 110 64 110 110 64 64 108 61
Notes: Dependent variable: columns (1)–(6), log GDP per capita (PPP basis) in 1995, current prices (from the World Bank’s
World Development Indicators 1999); columns (7)–(8), log output per worker in 1988 from Hall and Jones (1999). Average
protection against expropriation risk is measured on a scale from 0 to 10, where a higher score means more protection against
expropriation, averaged over 1985 to 1995, from Political Risk Services. Standard errors are in parentheses. In regressions
with continent dummies, the dummy for America is omitted. See Appendix Table A1 for more detailed variable definitions
and sources. Of the countries in our base sample, Hall and Jones do not report output per worker in the Bahamas, Ethiopia,
and Vietnam.
1379VOL. 91 NO. 5 ACEMOGLU ET AL.: THE COLONIAL ORIGINS OF DEVELOPMENT

downwards. All of these problems could be
solved if we had an instrument for institutions.
Such an instrument must be an important factor
in accounting for the institutional variation that
we observe, but have no direct effect on perfor-
mance. Our discussion in Section I suggests that
settler mortality during the time of colonization
is a plausible instrument.
III. Mortality of Early Settlers
A. Sources of European Mortality
in the Colonies
In this subsection, we give a brief overview
of the sources of mortality facing potential set-
tlers. Malaria (particularly Plasmodium falcipo-
rum) and yellow fever were the major sources
of European mortality in the colonies. In the
tropics, these two diseases accounted for 80
percent of European deaths, while gastrointes-
tinal diseases accounted for another 15 percent
(Curtin, 1989 p. 30). Throughout the nineteenth
century, areas without malaria and yellow fever,
such as New Zealand, were more healthy than
Europe because the major causes of death in
Europe—tuberculosis, pneumonia, and small-
pox—were rare in these places (Curtin, 1989
p. 13).
Both malaria and yellow fever are transmit-
ted by mosquito vectors. In the case of malaria,
the main transmitter is the Anopheles gambiae
complex and the mosquito Anopheles funestus,
while the main carrier of yellow fever is Aedes
aegypti. Both malaria and yellow fever vectors
tend to live close to human habitation.
In places where the malaria vector is present,
such as the West African savanna or forest, an
individual can get as many as several hundred
infectious mosquito bites a year. For a person
without immunity, malaria (particularly Plas-
modium falciporum) is often fatal, so Europe-
ans in Africa, India, or the Caribbean faced very
high death rates. In contrast, death rates for the
adult local population were much lower (see
Curtin [1964] and the discussion in our intro-
duction above). Curtin (1998 pp. 7–8) describes
this as follows:
Children in West Africa ... would be in-
fected with malaria parasites shortly after
birth and were frequently reinfected after-
wards; if they lived beyond the age of
about five, they acquired an apparent im-
munity. The parasite remained with them,
normally in the liver, but clinical symp-
toms were rare so long as they continued
to be infected with the same species of P.
falciporum.
FIGURE 2. OLS RELATIONSHIP BETWEEN EXPROPRIATION RISK AND INCOME
1380 THE AMERICAN ECONOMIC REVIEW DECEMBER 2001

The more recent books on malariology confirm
this conclusion. For example, “In stable en-
demic areas a heavy toll of morbidity and mor-
tality falls on young children but malaria is a
relatively mild condition in adults” (Herbert M.
Gilles and David A. Warrell, 1993 p. 64; see
also the classic reference on this topic, Leonard
J. Bruce-Chwatt, 1980 Chapter 4; Roy Porter,
1996).12 Similarly, the World Health Organiza-
tion (WHO) points out that in endemic malaria
areas of Africa and the Western Pacific today
“... the risk of malaria severity and death is
almost exclusively limited to non-immunes, be-
ing most serious for young children over six
months of age ... surviving children develop their
own immunity between the age of 3–5 years”
(Jose A. Najera and Joahim Hempel, 1996).
People in areas where malaria is endemic are
also more likely to have genetic immunity
against malaria. For example, they tend to have
the sickle-cell trait, which discourages the mul-
tiplication of parasites in the blood, or deficien-
cies in glucose-6-phosphate dehydrogenase and
thalassaemia traits, which also protect against
malaria. Porter (1996 p. 34) writes: “In such a
process, ... , close to 100 percent of Africans
acquired a genetic trait that protects them
against vivax malaria and probably against fal-
ciporum malaria as well.” Overall, the WHO es-
timates that malaria kills about 1 million people
per year, most of them children. It does not, how-
ever, generally kill adults who grew up in malaria-
endemic areas (see Najera and Hempel, 1996).
Although yellow fever’s epidemiology is
quite different from malaria, it was also much
more fatal to Europeans than to non-Europeans
who grew up in areas where yellow fever com-
monly occurred.13 Yellow fever leaves its sur-
viving victims with a lifelong immunity, which
also explains its epidemic pattern, relying on a
concentrated nonimmune population. Curtin
(1998 p. 10) writes: “Because most Africans
had passed through a light case early in life,
yellow fever in West Africa was a strangers’
disease, attacking those who grew up else-
where.” Similarly, Michael B. A. Oldstone
(1998 p. 49) writes:
Most Black Africans and their descen-
dants respond to yellow fever infection
with mild to moderate symptoms such as
headache, fever, nausea, and vomiting,
and then recover in a few days. This out-
come reflects the long relationship be-
tween the virus and its indigenous hosts,
who through generations of exposure to
the virus have evolved resistance.
In contrast, fatality rates among nonimmune
adults, such as Europeans, could be as high as
90 percent.
Advances in medical science have reduced
the danger posed by malaria and yellow fever.
Yellow fever is mostly eradicated (Oldstone,
1998 Chapter 5), and malaria has been eradi-
cated in many areas. Europeans developed
methods of dealing with these diseases that
gradually became more effective in the second
half of the nineteenth century. For example,
they came to understand that high doses of
quinine, derived from the cinchona bark, acted
as a prophylactic and prevented infection or
reduced the severity of malaria. They also
started to undertake serious mosquito eradica-
tion efforts and protect themselves against mos-
quito bites. Further, Europeans also learned that
an often effective method of reducing mortality
from yellow fever is flight from the area, since
the transmitter mosquito, Aedes aegypti, has only
a short range. Nevertheless, during much of the
nineteenth century, there was almost a complete
misunderstanding of the nature of both diseases.
For example, the leading theory for malaria was
that it was caused by “miasma” from swamps, and
quinine was not used widely. The role of small
collections of water to breed mosquitoes and
transmit these diseases was not understood. It was
only in the late nineteenth century that Europeans
started to control these diseases.14
12 Because malaria species are quite local, a person may
have immunity to the local version of malaria, but be highly
vulnerable to malaria a short distance away. This is proba-
bly the explanation for why Africans had such high mortal-
ity when they were forced to move by colonial powers.
(Curtin et al., 1995 p. 463).
13 Because yellow fever struck Europeans as an epi-
demic, many of the very high death rates we report below
for European troops are from yellow fever.
14 Even during the early twentieth century, there was
much confusion about the causes of malaria and yellow
1381VOL. 91 NO. 5 ACEMOGLU ET AL.: THE COLONIAL ORIGINS OF DEVELOPMENT

These considerations, together with the data
we have on the mortality of local people and
population densities before the arrival of Euro-
peans, make us believe that settler mortality is a
plausible instrument for institutional develop-
ment: these diseases affected European settle-
ment patterns and the type of institutions they
set up, but had little effect on the health and
economy of indigenous people.15
A final noteworthy feature, helpful in in-
terpreting our results below, is that malaria
prevalence depends as much on the microcli-
mate of an area as on its temperature and
humidity, or on whether it is in the tropics;
high altitudes reduce the risk of infection, so
in areas of high altitude, where “hill stations”
could be set up, such as Bogota in Colombia,
mortality rates were typically lower than in
wet coastal areas. However, malaria could
sometimes be more serious in high-altitude
areas. For example, Curtin (1989 p. 47) points
out that in Ceylon mortality was lower in the
coast than the highlands because rains in the
coast washed away the larvae of the transmit-
ter mosquitoes. Similarly, in Madras many
coastal regions were free of malaria, while
northern India had high rates of infection.
Curtin (1998 Chapter 7) also illustrates how
there were marked differences in the preva-
lence of malaria within small regions of
Madagascar. This suggests that mortality
rates faced by Europeans are unlikely to be a
proxy for some simple geographic or climac-
tic feature of the country.
B. Data on Potential Settler Mortality
Our data on the mortality of European set-
tlers come largely from the work of Philip
Curtin. Systematic military medical record
keeping began only after 1815, as an attempt
to understand why so many soldiers were
dying in some places. The first detailed stud-
ies were retrospective and dealt with British
forces between 1817 and 1836. The United
States and French governments quickly
adopted similar methods (Curtin, 1989 pp. 3,
5). Some early data are also available for the
Dutch East Indies. By the 1870’s, most Euro-
pean countries published regular reports on
the health of their soldiers.
The standard measure is annualized deaths
per thousand mean strength. This measure
reports the death rate among 1,000 soldiers
where each death is replaced with a new soldier.
Curtin (1989, 1998) reviews in detail the con-
struction of these estimates for particular places
and campaigns, and assesses which data should
be considered reliable.
Curtin (1989), Death by Migration, deals
primarily with the mortality of European
troops from 1817 to 1848. At this time mod-
ern medicine was still in its infancy, and the
European militaries did not yet understand
how to control malaria and yellow fever.
These mortality rates can therefore be inter-
preted as reasonable estimates of settler mor-
tality. They are consistent with substantial
evidence from other sources (see, for exam-
ple, Curtin [1964, 1968]). Curtin (1998), Dis-
ease and Empire, adds similar data on the
mortality of soldiers in the second half of the
nineteenth century.16 In all cases, we use the
fever. The Washington Post on Nov. 2, 1900 wrote: “Of all
the silly and nonsensical rigmarole of yellow fever that has
yet found its way into print ... the silliest beyond compare is
to be found in the arguments and theories generated by a
mosquito hypothesis” (quoted in Oldstone, 1998 pp.
64–65).
Many campaigns during the nineteenth century had very
high mortality rates. For example, the French campaign in
Madagascar during the 1890’s and French attempts to build
the Panama Canal during the 1880’s were mortality disas-
ters, the first due to malaria, the second due to yellow fever
(see Curtin, 1998, and David McCullogh, 1977). In Panama,
to stop ants the French used water pots under the legs of
beds in barracks and hospitals. These pots provided an ideal
milieu for the breeding of Aedes aegypti, causing very high
rates of mortality (Oldstone, 1998 p. 66).
15 In Acemoglu et al. (2001), we document that many of
these areas in the tropical zone were richer and more
densely settled in 1500 than the temperate areas later settled
by the Europeans. This also supports the notion that the
disease environment did not create an absolute disadvantage
for these countries.
16 These numbers have to be used with more care be-
cause there was a growing awareness of how to avoid
epidemics of the worst tropical diseases, at least during
short military campaigns. For example, the campaign in
Ethiopia at the end of the nineteenth century had very low
mortality rates because it was short and well managed (see
Figure 1). Although the mortality rates from this successful
campaign certainly underestimate the mortality rates faced
1382 THE AMERICAN ECONOMIC REVIEW DECEMBER 2001

earliest available number for each country,
reasoning that this is the best estimate of the
mortality rates that settlers would have faced,
at least until the twentieth century.
The main gap in the Curtin data is for South
America since the Spanish and Portuguese
militaries did not keep good records of mor-
tality. Hector Gutierrez (1986) used Vatican
records to construct estimates for the mortal-
ity rates of bishops in Latin America from
1604 to 1876. Because these data overlap
with the Curtin estimates for several coun-
tries, we are able to construct a data series for
South America.17 Curtin (1964) also provides
estimates of mortality in naval squadrons for
different regions which we can use to gener-
ate alternative estimates of mortality in South
America. Appendix B in Acemoglu et al.
(2000), which is available from the authors,
gives a detailed discussion of how these data
are constructed, and Appendix Table A5
(available from the authors), shows that these
alternative methods produce remarkably sim-
ilar results. Appendix Table A2 lists our main
estimates, and Table A1 gives information
about sources.
IV. Institutions and Performance: IV Results
A. Determinants of Current Institutions
Equation (1) describes the relationship be-
tween current institutions and log GDP. In ad-
dition we have
(2) Ri 5 lR 1 bR Ci 1 X9igR 1 nRi ,
(3) Ci 5 lC 1 bC Si 1 X9igC 1 nCi ,
(4) Si 5 lS 1 bSlog Mi 1 X9igS 1 nSi ,
where R is the measure of current institutions
(protection against expropriation between 1985
and 1995), C is our measure of early (circa
1900) institutions, S is the measure of European
settlements in the colony (fraction of the popu-
lation with European descent in 1900), and M is
mortality rates faced by settlers. X is a vector of
covariates that affect all variables.
The simplest identification strategy might be
to use Si (or Ci) as an instrument for Ri in
equation (1), and we report some of these re-
gressions in Table 8. However, to the extent that
settlers are more likely to migrate to richer areas
and early institutions reflect other characteris-
tics that are important for income today, this
identification strategy would be invalid (i.e., Ci
and Si could be correlated with «i). Instead, we
use the mortality rates faced by the settlers, log
Mi , as an instrument for Ri. This identification
strategy will be valid as long as log Mi is
uncorrelated with «i—that is, if mortality rates
of settlers between the seventeenth and nine-
teenth centuries have no effect on income today
other than through their influence on institu-
tional development. We argued above that this
exclusion restriction is plausible.
Figure 3 illustrates the relationship between the
(potential) settler mortality rates and the index of
institutions. We use the logarithm of the settler
mortality rates, since there are no theoretical rea-
sons to prefer the level as a determinant of insti-
tutions rather than the log, and using the log
ensures that the extreme African mortality rates do
not play a disproportionate role. As it happens,
there is an almost linear relationship between the
log settler mortality and our measure of institu-
tions. This relationship shows that ex-colonies
where Europeans faced higher mortality rates
have substantially worse institutions today.
In Table 3, we document that this relationship
works through the channels hypothesized in Sec-
tion I. In particular, we present OLS regressions of
equations (2), (3), and (4). In the top panel, we
regress the protection against expropriation vari-
able on the other variables. Column (1) uses con-
straints faced by the executive in 1900 as the
regressor, and shows a close association between
early institutions and institutions today. For exam-
ple, past institutions alone explain 20 percent of
the variation in the index of current institutions.
The second column adds the latitude variable,
by potential settlers in Ethiopia, we did not exclude this
country because excluding it would have helped our hy-
pothesis.
17 Combining data from a variety of sources will in-
troduce measurement error in our estimates of settler
mortality. Nevertheless, since we are using settler mor-
tality as an instrument, this measurement error does not
lead to inconsistent estimates of the effect of institutions
on performance.
1383VOL. 91 NO. 5 ACEMOGLU ET AL.: THE COLONIAL ORIGINS OF DEVELOPMENT

with little effect on the estimate. Columns (3) and
(4) use the democracy index, and confirm the
results in columns (1) and (2).
Both constraints on the executive and democ-
racy indices assign low scores to countries that
were colonies in 1900, and do not use the ear-
liest postindependence information for Latin
American countries and the Neo-Europes. In
columns (5) and (6), we adopt an alternative
approach and use the constraints on the execu-
tive in the first year of independence and also
control separately for time since independence.
The results are similar, and indicate that early
institutions tend to persist.
Columns (7) and (8) show the association be-
tween protection against expropriation and Euro-
pean settlements. The fraction of Europeans in
1900 alone explains approximately 30 percent of
the variation in our institutions variable today.
Columns (9) and (10) show the relationship be-
tween the protection against expropriation vari-
able and the mortality rates faced by settlers. This
specification will be the first stage for our main
two-stage least-squares estimates (2SLS). It shows
that settler mortality alone explains 27 percent of
the differences in institutions we observe today.
Panel B of Table 3 provides evidence in
support of the hypothesis that early institutions
were shaped, at least in part, by settlements, and
that settlements were affected by mortality. Col-
umns (1)–(2) and (5)–(6) relate our measure of
constraint on the executive and democracy in
1900 to the measure of European settlements in
1900 (fraction of the population of European
decent). Columns (3)–(4) and (7)–(8) relate the
same variables to settler mortality. These regres-
sions show that settlement patterns explain around
50 percent of the variation in early institutions.
Finally, columns (9) and (10) show the relation-
ship between settlements and mortality rates.
B. Institutions and Economic Performance
Two-stage least-squares estimates of equa-
tion (1) are presented in Table 4. Protection
against expropriation variable, Ri , is treated as
endogenous, and modeled as
(5) Ri 5 z 1 b log Mi 1 X9id 1 vi ,
where Mi is the settler mortality rate in 1,000
mean strength. The exclusion restriction is that
this variable does not appear in (1).
FIGURE 3. FIRST-STAGE RELATIONSHIP BETWEEN SETTLER MORTALITY AND EXPROPRIATION RISK
1384 THE AMERICAN ECONOMIC REVIEW DECEMBER 2001

Panel A of Table 4 reports 2SLS estimates
of the coefficient of interest, a from equation
(1) and Panel B gives the corresponding first
stages.18 Column (1) displays the strong first-
stage relationship between (log) settler mortal-
ity and current institutions in our base sample,
also shown in Table 3. The corresponding 2SLS
estimate of the impact of institutions on income
per capita is 0.94. This estimate is highly sig-
nificant with a standard error of 0.16, and in fact
larger than the OLS estimates reported in
Table 2. This suggests that measurement error
in the institutions variables that creates attenu-
ation bias is likely to be more important than
reverse causality and omitted variables biases.
Here we are referring to “measurement error”
broadly construed. In reality the set of institu-
tions that matter for economic performance is
very complex, and any single measure is bound
to capture only part of the “true institutions,”
18 We have also run these regressions with standard
errors corrected for possible clustering of the mortality rates
assigned to countries in the same disease environment. This
clustering has little effect on the standard errors, and does
not change our results.
TABLE 3—DETERMINANTS OF INSTITUTIONS
(1) (2) (3) (4) (5) (6) (7) (8) (9) (10)
Panel A Dependent Variable Is Average Protection Against Expropriation Risk in 1985–1995
Constraint on executive in 0.32 0.26
1900 (0.08) (0.09)
Democracy in 1900 0.24 0.21
(0.06) (0.07)
Constraint on executive in first 0.25 0.22
year of independence (0.08) (0.08)
European settlements in 1900 3.20 3.00
(0.61) (0.78)
Log European settler mortality 20.61 20.51
(0.13) (0.14)
Latitude 2.20 1.60 2.70 0.58 2.00
(1.40) (1.50) (1.40) (1.51) (1.34)
R2 0.2 0.23 0.24 0.25 0.19 0.24 0.3 0.3 0.27 0.3
Number of observations 63 63 62 62 63 63 66 66 64 64
Panel B
Dependent Variable Is Constraint
on Executive in 1900
Dependent Variable Is
Democracy in 1900
Dependent
Variable Is
European
Settlements in
1900
European settlements in 1900 5.50 5.40 8.60 8.10
(0.73) (0.93) (0.90) (1.20)
Log European settler mortality 20.82 20.65 21.22 20.88 20.11 20.07
(0.17) (0.18) (0.24) (0.25) (0.02) (0.02)
Latitude 0.33 3.60 1.60 7.60 0.87
(1.80) (1.70) (2.30) (2.40) (0.19)
R2 0.46 0.46 0.25 0.29 0.57 0.57 0.28 0.37 0.31 0.47
Number of observations 70 70 75 75 67 67 68 68 73 73
Notes: All regressions are OLS. Standard errors are in parentheses. Regressions with constraint on executive in first year of
independence also include years since independence as a regressor. Average protection against expropriation risk is on a scale
from 0 to 10, where a higher score means more protection against expropriation of private investment by government,
averaged over 1985 to 1995. Constraint on executive in 1900 is on a scale from 1 to 7, with a higher score indicating more
constraints. Democracy in 1900 is on a scale from 0 to 10, with a higher score indicating more democracy. European
settlements is percent of population that was European or of European descent in 1900. See Appendix Table A1 for more
detailed variable definitions and sources.
1385VOL. 91 NO. 5 ACEMOGLU ET AL.: THE COLONIAL ORIGINS OF DEVELOPMENT

creating a typical measurement error problem.
Moreover, what matters for current income is
presumably not only institutions today, but also
institutions in the past. Our measure of institu-
tions which refers to 1985–1995 will not be
perfectly correlated with these.19
Does the 2SLS estimate make quantitative
sense? Does it imply that institutional differences
can explain a significant fraction of income dif-
19 We can ascertain, to some degree, whether the differ-
ence between OLS and 2SLS estimates could be due to
measurement error in the institutions variable by making
use of an alternative measure of institutions, for example,
the constraints on the executive measure. Using this mea-
sure as an instrument for the protection against expropria-
tion index would solve the measurement error, but not the
endogeneity problem. This exercise leads to an estimate of
the effect of protection against expropriation equal to 0.87
(with standard error 0.16). This suggests that “measurement
error” in the institutions variables (or the “signal-to-noise
ratio” in the institutions variable) is of the right order of
magnitude to explain the difference between the OLS and
2SLS estimates.
TABLE 4—IV REGRESSIONS OF LOG GDP PER CAPITA
Base
sample
(1)
Base
sample
(2)
Base sample
without
Neo-Europes
(3)
Base sample
without
Neo-Europes
(4)
Base
sample
without
Africa
(5)
Base
sample
without
Africa
(6)
Base
sample
with
continent
dummies
(7)
Base
sample
with
continent
dummies
(8)
Base
sample,
dependent
variable is
log output
per worker
(9)
Panel A: Two-Stage Least Squares
Average protection against 0.94 1.00 1.28 1.21 0.58 0.58 0.98 1.10 0.98
expropriation risk 1985–1995 (0.16) (0.22) (0.36) (0.35) (0.10) (0.12) (0.30) (0.46) (0.17)
Latitude 20.65 0.94 0.04 21.20
(1.34) (1.46) (0.84) (1.8)
Asia dummy 20.92 21.10
(0.40) (0.52)
Africa dummy 20.46 20.44
(0.36) (0.42)
“Other” continent dummy 20.94 20.99
(0.85) (1.0)
Panel B: First Stage for Average Protection Against Expropriation Risk in 1985–1995
Log European settler mortality 20.61 20.51 20.39 20.39 21.20 21.10 20.43 20.34 20.63
(0.13) (0.14) (0.13) (0.14) (0.22) (0.24) (0.17) (0.18) (0.13)
Latitude 2.00 20.11 0.99 2.00
(1.34) (1.50) (1.43) (1.40)
Asia dummy 0.33 0.47
(0.49) (0.50)
Africa dummy 20.27 20.26
(0.41) (0.41)
“Other” continent dummy 1.24 1.1
(0.84) (0.84)
R2 0.27 0.30 0.13 0.13 0.47 0.47 0.30 0.33 0.28
Panel C: Ordinary Least Squares
Average protection against 0.52 0.47 0.49 0.47 0.48 0.47 0.42 0.40 0.46
expropriation risk 1985–1995 (0.06) (0.06) (0.08) (0.07) (0.07) (0.07) (0.06) (0.06) (0.06)
Number of observations 64 64 60 60 37 37 64 64 61
Notes: The dependent variable in columns (1)–(8) is log GDP per capita in 1995, PPP basis. The dependent variable in column (9) is log output
per worker, from Hall and Jones (1999). “Average protection against expropriation risk 1985–1995” is measured on a scale from 0 to 10, where
a higher score means more protection against risk of expropriation of investment by the government, from Political Risk Services. Panel A
reports the two-stage least-squares estimates, instrumenting for protection against expropriation risk using log settler mortality; Panel B reports
the corresponding first stage. Panel C reports the coefficient from an OLS regression of the dependent variable against average protection against
expropriation risk. Standard errors are in parentheses. In regressions with continent dummies, the dummy for America is omitted. See Appendix
Table A1 for more detailed variable descriptions and sources.
1386 THE AMERICAN ECONOMIC REVIEW DECEMBER 2001

ferences across countries? Let us once again com-
pare two “typical” countries with high and low
expropriation risk, Nigeria and Chile (these coun-
tries are typical for the IV regression in the sense
that they are practically on the regression line).
Our 2SLS estimate, 0.94, implies that the 2.24
differences in expropriation risk between these
two countries should translate into 206 log point
(approximately 7-fold) difference. In practice, the
presence of measurement error complicates this
interpretation, because some of the difference be-
tween Nigeria and Chile’s expropriation index
may reflect measurement error. Therefore, the
7-fold difference is an upper bound. In any case,
the estimates in Table 4 imply a substantial, but
not implausibly large, effect of institutional differ-
ences on income per capita.
Column (2) shows that adding latitude does
not change the relationship; the institutions
coefficient is now 1.00 with a standard error of
0.22.20 Remarkably, the latitude variable now
has the “wrong” sign and is insignificant. This
result suggests that many previous studies may
have found latitude to be a significant determi-
nant of economic performance because it is
correlated with institutions (or with the exoge-
nous component of institutions caused by early
colonial experience).
Columns (3) and (4) document that our results
are not driven by the Neo-Europes. When we
exclude the United States, Canada, Australia, and
New Zealand, the estimates remain highly signif-
icant, and in fact increase a little. For example, the
coefficient for institutions is now 1.28 (s.e. 5
0.36) without the latitude control, and 1.21 (s.e. 5
0.35) when we control for latitude. Columns (5)
and (6) show that our results are also robust to
dropping all the African countries from our sam-
ple. The estimates without Africa are somewhat
smaller, but also more precise. For example, the
coefficient for institutions is 0.58 (s.e. 5 0.1)
without the latitude control, and still 0.58 (s.e. 5
0.12) when we control for latitude.21
In columns (7) and (8), we add continent dum-
mies to the regressions (for Africa, Asia, and
other, with America as the omitted group). The
addition of these dummies does not change the
estimated effect of institutions, and the dummies
are jointly insignificant at the 5-percent level,
though the dummy for Asia is significantly differ-
ent from that of America. The fact that the African
dummy is insignificant suggests that the reason
why African countries are poorer is not due to
cultural or geographic factors, but mostly ac-
counted for by the existence of worse institutions
in Africa. Finally, in column (9) we repeat our
basic regression using log of output per worker as
calculated by Hall and Jones (1999). The result is
very close to our baseline result. The 2SLS coef-
ficient is 0.98 instead of 0.94 as in column (1).22
This shows that whether we use income per capita
or output per worker has little effect on our results.
Overall, the results in Table 4 show a large effect
of institutions on economic performance. In the
rest of the paper, we investigate the robustness of
these results.23
20 In 2SLS estimation, all covariates that are included in
the second stage, such as latitude, are also included in the
first stage. When these first-stage effects are of no major
significance for our argument, we do not report them in the
tables to save space.
21 We should note at this point that if we limit the sample
to African countries only, the first-stage relationship using
the protection against expropriation variable becomes con-
siderably weaker, and the 2SLS effect of institutions is no
longer significant. The 2SLS effect of institutions continue
to be significant when we use some (but not all) measures of
institutions. Therefore, we conclude that the relationship
between settler mortality and institutions is weaker within
Africa.
22 The results with other covariates are also very similar.
We repeated the same regressions using a variety of alter-
native measures of institutions, including constraints on the
executive from the Polity III data set, an index of law and
order tradition from Political Risk Services, a measure of
property rights from the Heritage Foundation, a measure of
rule of law from the Fraser Institute, and the efficiency
of the judiciary from Business International. The results
and the magnitudes are very similar to those reported in
Table 4. We also obtained very similar results with the 1970
values for the constraints on the executive and income per
capita in 1970, which show that the relationship between
institutional measures and income per capita holds across
time periods. These results are reported in the Appendix of
the working paper version, and are also available from the
authors.
23 In the working paper version, we also investigated the
robustness of our results in different subsamples with vary-
ing degrees of data quality and different methods of con-
structing the mortality estimates. The results change very
little, for example, when we use data only from Curtin
(1989), Death by Migration, when we do not assign mor-
tality rates from neighboring disease environments, when
1387VOL. 91 NO. 5 ACEMOGLU ET AL.: THE COLONIAL ORIGINS OF DEVELOPMENT

V. Robustness
A. Additional Controls
The validity of our 2SLS results in Table 4
depends on the assumption that settler mortality in
the past has no direct effect on current economic
performance. Although this presumption appears
reasonable (at least to us), here we substantiate it
further by directly controlling for many of the
variables that could plausibly be correlated with
both settler mortality and economic outcomes, and
checking whether the addition of these variables
affects our estimates.24 Overall, we find that our
results change remarkably little with the inclusion
of these variables, and many variables emphasized
in previous work become insignificant once the
effect of institutions is controlled for.
La Porta et al. (1999) argue for the impor-
tance of colonial origin (identity of the main
colonizing country) as a determinant of current
institutions. The identity of the colonial power
could also matter because it might have an
effect through culture, as argued by David
S. Landes (1998). In columns (1) and (2) of
Table 5, we add dummies for British and French
colonies (colonies of other nations are the omit-
ted group). This has little affect on our results.
Moreover, the French dummy in the first
stage is estimated to be zero, while the British
dummy is positive, and marginally significant.
Therefore, as suggested by La Porta et al.
(1998), British colonies appear to have better
institutions, but this effect is much smaller and
weaker than in a specification that does not
control for the effect of settler mortality on
institutional development.25 Therefore, it ap-
pears that British colonies are found to perform
substantially better in other studies in large part
because Britain colonized places where settle-
ments were possible, and this made British col-
onies inherit better institutions. To further
investigate this issue, columns (3) and (4) esti-
mate our basic regression for British colonies
only. They show that both the relationship be-
tween settler mortality and institutions and that
between institutions and income in this sample
of 25 British colonies are very similar to those
in our base sample. For example, the 2SLS
estimate of the effect of institutions on income
is now 1.07 (s.e. 5 0.24) without controlling for
latitude and 1.00 (s.e. 5 0.22) with latitude.
These results suggest that the identity of the
colonizer is not an important determinant of
colonization patterns and subsequent institu-
tional development.
von Hayek (1960) and La Porta et al. (1999)
also emphasize the importance of legal origin. In
columns (5) and (6), we control for legal origin. In
our sample, all countries have either French or
British legal origins, so we simply add a dummy
for French legal origin (many countries that are
not French colonies nonetheless have French legal
origin). Our estimate of the effect of institutions
on income per capita is unaffected.26
An argument dating back to Max Weber
views religion as a key determinant of economic
performance. To control for this, in columns (7)
and (8), we add the fraction of the populations
that are Catholic, Muslim, and of other reli-
gions, with Protestants as the omitted group. In
the table we report the joint significance level
( p-value) of the corresponding F-statistic for
these dummies as well as the 2SLS estimate of
the use data for Latin America from naval stations instead of
bishops, and when we do not use data from small African
samples. These results are available in Appendix Table A5
available from the authors, or in Acemoglu et al. (2000).
24 Joseph N. Altonji et al. (2000) develop an econometric
methodology to assess the importance of omitted variable
bias. The basic idea is that if the estimate of the coefficient
of interest does not change as additional covariates are
included in the regression, it is less likely to change if we
were able to add some of the missing omitted variables. Our
methodology here is an informal version of this approach.
25 Moreover, the British colonial dummy is negative and
significant in the second stage. The net effect of being a British
colony on income per capita is in fact negative. More specif-
ically, British colonies have, on average, an index of institution
that is 0.63 points lower. Given the 2SLS estimate of 1.10,
this translates into 69 log points higher income per capita
for British colonies (1.10 3 63 ’ 69). The second-stage
effect of being a British colony is 278 log points, im-
plying 29 log point (approximately 10 percent) negative
net effect of being a British colony. A possible explana-
tion for this pattern is that (Anglo-Saxon?) researchers
are overestimating how “bad” French institutions are, and
the second-stage regression is correcting for this.
26 The first stage shows that French legal origin is asso-
ciated with worse institutions, but similarly, the net effect of
having French legal origin is actually positive: 267 3
1.1 1 89 5 15 log points (approximately 15 percent).
1388 THE AMERICAN ECONOMIC REVIEW DECEMBER 2001

the effect of institutions.27 Finally, column (9)
adds all the variables in this table simulta-
neously. Again, these controls have very little
effect on our main estimate.
Another concern is that settler mortality is
correlated with climate and other geographic
characteristics. Our instrument may therefore
be picking up the direct effect of these vari-
ables. We investigate this issue in Table 6. In
columns (1) and (2), we add a set of temper-
ature and humidity variables (all data from
Philip M. Parker, 1997). In the table we
report joint significance levels for these vari-
ables. Again, they have little effect on our
estimates.
27 The religion dummies are significant in the first stage,
but once again they are estimated to have offsetting effects
in the second stage, implying little net effect of religion on
income.
TABLE 5—IV REGRESSIONS OF LOG GDP PER CAPITA WITH ADDITIONAL CONTROLS
Base
sample
(1)
Base
sample
(2)
British
colonies
only
(3)
British
colonies
only
(4)
Base
sample
(5)
Base
sample
(6)
Base
sample
(7)
Base
sample
(8)
Base
sample
(9)
Panel A: Two-Stage Least Squares
Average protection against 1.10 1.16 1.07 1.00 1.10 1.20 0.92 1.00 1.10
expropriation risk, 1985–1995 (0.22) (0.34) (0.24) (0.22) (0.19) (0.29) (0.15) (0.25) (0.29)
Latitude 20.75 21.10 20.94 21.70
(1.70) (1.56) (1.50) (1.6)
British colonial dummy 20.78 20.80
(0.35) (0.39)
French colonial dummy 20.12 20.06 0.02
(0.35) (0.42) (0.69)
French legal origin dummy 0.89 0.96 0.51
(0.32) (0.39) (0.69)
p-value for religion variables [0.001] [0.004] [0.42]
Panel B: First Stage for Average Protection Against Expropriation Risk in 1985–1995
Log European settler mortality 20.53 20.43 20.59 20.51 20.54 20.44 20.58 20.44 20.48
(0.14) (0.16) (0.19) (0.14) (0.13) (0.14) (0.13) (0.15) (0.18)
Latitude 1.97 2.10 2.50 2.30
(1.40) (1.30) (1.50) (1.60)
British colonial dummy 0.63 0.55
(0.37) (0.37)
French colonial dummy 0.05 20.12 20.25
(0.43) (0.44) (0.89)
French legal origin 20.67 20.7 20.05
(0.33) (0.32) (0.91)
R2 0.31 0.33 0.30 0.30 0.32 0.35 0.32 0.35 0.45
Panel C: Ordinary Least Squares
Average protection against 0.53 0.47 0.61 0.47 0.56 0.56 0.53 0.47 0.47
expropriation risk, 1985–1995 (0.19) (0.07) (0.09) (0.06) (0.06) (0.06) (0.06) (0.06) (0.06)
Number of observations 64 64 25 25 64 64 64 64 64
Notes: Panel A reports the two-stage least-squares estimates with log GDP per capita (PPP basis) in 1995 as dependent variable,
and Panel B reports the corresponding first stage. The base case in columns (1) and (2) is all colonies that were neither French nor
British. The religion variables are included in the first stage of columns (7) and (8) but not reported here (to save space). Panel C
reports the OLS coefficient from regressing log GDP per capita on average protection against expropriation risk, with the other
control variables indicated in that column (full results not reported to save space). Standard errors are in parentheses and p-values
for joint significance tests are in brackets. The religion variables are percentage of population that are Catholics, Muslims, and
“other” religions; Protestant is the base case. Our sample is all either French or British legal origin (as defined by La Porta et al.,
1999).
1389VOL. 91 NO. 5 ACEMOGLU ET AL.: THE COLONIAL ORIGINS OF DEVELOPMENT

A related concern is that in colonies where
Europeans settled, the current population con-
sists of a higher fraction of Europeans. One
might be worried that we are capturing the
direct effect of having more Europeans (who
perhaps brought a “European culture” or spe-
cial relations with Europe). To control for
this, we add the fraction of the population of
European descent in columns (3) and (4) of
Table 6. This variable is insignificant, while
the effect of institutions remains highly sig-
nificant, with a coefficient of 0.96 (s.e. 5
0.28). In columns (5) and (6), we control for
measures of natural resources, soil quality (in
practice soil types), and for whether the coun-
try is landlocked. All these controls are insig-
nificant, and have little effect on our 2SLS
estimate of the effect of institutions on in-
come per capita.
In columns (7) and (8), we include ethno-
linguistic fragmentation as another control
and treat it as exogenous. Now the coefficient
TABLE 6—ROBUSTNESS CHECKS FOR IV REGRESSIONS OF LOG GDP PER CAPITA
Base
sample
(1)
Base
sample
(2)
Base
sample
(3)
Base
sample
(4)
Base
sample
(5)
Base
sample
(6)
Base
sample
(7)
Base
sample
(8)
Base
sample
(9)
Panel A: Two-Stage Least Squares
Average protection against 0.84 0.83 0.96 0.99 1.10 1.30 0.74 0.79 0.71
expropriation risk, 1985–1995 (0.19) (0.21) (0.28) (0.30) (0.33) (0.51) (0.13) (0.17) (0.20)
Latitude 0.07 20.67 21.30 20.89 22.5
(1.60) (1.30) (2.30) (1.00) (1.60)
p-value for temperature variables [0.96] [0.97] [0.77]
p-value for humidity variables [0.54] [0.54] [0.62]
Percent of European descent in 1975 20.08 0.03 0.3
(0.82) (0.84) (0.7)
p-value for soil quality [0.79] [0.85] [0.46]
p-value for natural resources [0.82] [0.87] [0.82]
Dummy for being landlocked 0.64 0.79 0.75
(0.63) (0.83) (0.47)
Ethnolinguistic fragmentation 21.00 21.10 21.60
(0.32) (0.34) (0.47)
Panel B: First Stage for Average Protection Against Expropriation Risk in 1985–1995
Log European settler mortality 20.64 20.59 20.41 20.4 20.44 20.34 20.64 20.56 20.59
(0.17) (0.17) (0.14) (0.15) (0.16) (0.17) (0.15) (0.15) (0.21)
Latitude 2.70 0.48 2.20 2.30 4.20
(2.00) (1.50) (1.50) (1.40) (2.60)
R2 0.39 0.41 0.34 0.34 0.41 0.43 0.27 0.30 0.59
Panel C: Ordinary Least Squares
Average protection against 0.41 0.38 0.39 0.38 0.46 0.42 0.46 0.45 0.38
expropriation risk, 1985–1995 (0.06) (0.06) (0.06) (0.06) (0.07) (0.07) (0.05) (0.06) (0.06)
Notes: Panel A reports the two-stage least-squares estimates with log GDP per capita (PPP basis) in 1995, and Panel B reports
the corresponding first stages. Panel C reports the OLS coefficient from regressing log GDP per capita on average protection
against expropriation risk, with the other control variables indicated in that column (full results not reported to save space).
Standard errors are in parentheses and p-values for joint significance tests are in brackets. All regressions have 64
observations, except those including natural resources, which have 63 observations. The temperature and humidity variables
are: average, minimum, and maximum monthly high temperatures, and minimum and maximum monthly low temperatures,
and morning minimum and maximum humidity, and afternoon minimum and maximum humidity (from Parker, 1997).
Measures of natural resources are: percent of world gold reserves today, percent of world iron reserves today, percent of world
zinc reserves today, number of minerals present in country, and oil resources (thousands of barrels per capita). Measures of
soil quality/climate are steppe (low latitude), desert (low latitude), steppe (middle latitude), desert (middle latitude), dry steppe
wasteland, desert dry winter, and highland. See Appendix Table A1 for more detailed variable definitions and sources.
1390 THE AMERICAN ECONOMIC REVIEW DECEMBER 2001

of protection against expropriation is 0.74
(s.e. 5 0.13), which is only slightly smaller
than our baseline estimate. In Appendix A, we
show that the inclusion of an endogenous
variable positively correlated with income or
institutions will bias the coefficient on insti-
tutions downwards. Since ethnolinguistic
fragmentation is likely to be endogenous with
respect to development (i.e., ethnolinguistic
fragmentation tends to disappear after the for-
mation of centralized markets; see Weber
[1976] or Andersen [1983]) and is correlated
with settler mortality, the estimate of 0.74
likely understates the effect of institutions on
income. In column (9) of Table 6, we include
all these variables together. Despite the large
number of controls, protection against expro-
priation on income per capita is still highly
significant, with a somewhat smaller coeffi-
cient of 0.71 (s.e. 5 0.20), which is again
likely to understate the effect of institutions
on income because ethnolinguistic fragmen-
tation is treated as exogenous.
Finally, in Table 7, we investigate whether
our instrument could be capturing the general
effect of disease on development. Sachs and a
series of coauthors have argued for the impor-
tance of malaria and other diseases in explain-
ing African poverty (see, for example, Bloom
and Sachs, 1998; Gallup and Sachs, 1998;
Gallup et al., 1998). Since malaria was one of
the main causes of settler mortality, our esti-
mate may be capturing the direct effect of ma-
laria on economic performance. We are
skeptical of this argument since malaria preva-
lence is highly endogenous; it is the poorer
countries with worse institutions that have been
unable to eradicate malaria.28 While Sachs and
coauthors argue that malaria reduces output
through poor health, high mortality, and absen-
teeism, most people who live in high malaria
areas have developed some immunity to the
disease (see the discussion in Section III, sub-
section A). Malaria should therefore have little
direct effect on economic performance (though,
obviously, it will have very high social costs).
In contrast, for Europeans, or anyone else who
has not been exposed to malaria as a young
child, malaria is usually fatal, making malaria
prevalence a key determinant of European set-
tlements and institutional development.
In any case, controlling for malaria does not
change our results. We do this in columns (1)
and (2) by controlling for the fraction of the
population who live in an area where falcipo-
rum malaria is endemic in 1994 (as constructed
and used by Gallup et al., 1998). Since malaria
prevalence in 1994 is highly endogenous, the
argument in Appendix A implies that control-
ling for it directly will underestimate the effect
of institutions on performance. In fact, the co-
efficient on protection against expropriation is
now estimated to be somewhat smaller, 0.69
instead of 0.94 as in Table 4. Nevertheless,
the effect remains highly significant with a stan-
dard error of 0.25, while malaria itself is
insignificant.
In a comment on the working paper version
of our study, John W. McArthur and Sachs
(2001) discuss the role of geography and insti-
tutions in determining economic performance.
They accept our case for the importance of
institutions, but argue that more general speci-
fications show that the disease environment and
health characteristics of countries (their “geog-
raphy”) matter for economic performance. In
particular, they extend our work by controlling
for life expectancy and infant mortality, and
they also instrument for these health variables
using geographic variables such as latitude and
mean temperature. Table 7 also expands upon
the specifications that McArthur and Sachs sug-
gest. Columns (3)–(6) include life expectancy
and infant mortality as exogenous controls. The
estimates show a significant effect of institu-
tions on income, similar to, but smaller than,
our baseline estimates. Infant mortality is also
marginally significant. Since health is highly
endogenous, the coefficient on these variables
will be biased up, while the coefficient of insti-
tutions will be biased down (see Appendix A).
These estimates are therefore consistent with
28 For example, the United States eliminated malaria from
the Panama Canal Zone, and Australia eliminated it from
Queensland (see Crosby, 1986 pp. 141–42). Even in Africa,
there have been very successful campaigns against malaria,
including those in Algeria and that conducted by the Rio-Tinto
Zinc mining company in Zambia (then Northern Rhodesia).
The WHO’s Roll Back Malaria program contains a number of
effective recommendations for controlling malaria that are
relatively straightforward to implement if families have
enough money (e.g., insecticide-treated bed nets).
1391VOL. 91 NO. 5 ACEMOGLU ET AL.: THE COLONIAL ORIGINS OF DEVELOPMENT

institutions being the major determinant of in-
come per capita differences, with little effect
from geography/health variables.
Columns (7)–(9) report estimates from mod-
els that treat both health and institutions as
endogenous, and following McArthur and
Sachs, instrument for them using latitude, mean
temperature, and distance from the coast as in-
struments in addition to our instrument, settler
mortality. McArthur and Sachs (2001) report
that in these regressions the institution variable
is still significant, but geography/health are also
significant. In contrast to McArthur and Sachs’
results, we find that only institutions are signif-
TABLE 7—GEOGRAPHY AND HEALTH VARIABLES
(1) (2) (3) (4) (5) (6) (7) (8) (9) (10) (11)
Instrumenting only for average
protection against expropriation risk
Instrumenting for all
right-hand-side variables
Yellow fever
instrument for
average
protection against
expropriation risk
Panel A: Two-Stage Least Squares
Average protection against 0.69 0.72 0.63 0.68 0.55 0.56 0.69 0.74 0.68 0.91 0.90
expropriation risk, 1985–1995 (0.25) (0.30) (0.28) (0.34) (0.24) (0.31) (0.26) (0.24) (0.23) (0.24) (0.32)
Latitude 20.57 20.53 20.1
(1.04) (0.97) (0.95)
Malaria in 1994 20.57 20.60 20.62
(0.47) (0.47) (0.68)
Life expectancy 0.03 0.03 0.02
(0.02) (0.02) (0.02)
Infant mortality 20.01 20.01 20.01
(0.005) (0.006) (0.01)
Panel B: First Stage for Average Protection Against Expropriation Risk in 1985–1995
Log European settler mortality 20.42 20.38 20.34 20.30 20.36 20.29 20.41 20.40 20.40
(0.19) (0.19) (0.17) (0.18) (0.18) (0.19) (0.17) (0.17) (0.17)
Latitude 1.70 1.10 1.60 20.81 20.84 20.84
(1.40) (1.40) (1.40) (1.80) (1.80) (1.80)
Malaria in 1994 20.79 20.65
(0.54) (0.55)
Life expectancy 0.05 0.04
(0.02) (0.02)
Infant mortality 20.01 20.01
(0.01) (0.01)
Mean temperature 20.12 20.12 20.12
(0.05) (0.05) (0.05)
Distance from coast 0.57 0.55 0.55
(0.51) (0.52) (0.52)
Yellow fever dummy 21.10 20.81
(0.41) (0.38)
R2 0.3 0.31 0.34 0.35 0.32 0.34 0.37 0.36 0.36 0.10 0.32
Panel C: Ordinary Least Squares
Average protection against 0.35 0.35 0.28 0.28 0.29 0.28 0.35 0.29 0.29 0.48 0.39
expropriation risk, 1985–1995 (0.06) (0.06) (0.05) (0.05) (0.05) (0.05) (0.06) (0.05) (0.05) (0.06) (0.06)
Number of observations 62 62 60 60 60 60 60 59 59 64 64
Notes: Panel A reports the two-stage least-squares estimates with log GDP per capita (PPP basis) in 1995, and Panel B reports the
corresponding first stages. Panel C reports the coefficient from an OLS regression with log GDP per capita as the dependent variable and
average protection against expropriation risk and the other control variables indicated in each column as independent variables (full
results not reported to save space). Standard errors are in parentheses. Columns (1)–(6) instrument for average protection against
expropriation risk using log mortality and assume that the other regressors are exogenous. Columns (7)–(9) include as instruments
average temperature, amount of territory within 100 km of the coast, and latitude (from McArthur and Sachs, 2001). Columns (10)
and (11) use a dummy variable for whether or not a country was subject to yellow fever epidemics before 1900 as an instrument for
average protection against expropriation. See Appendix Table A1 for more detailed variable definitions and sources.
1392 THE AMERICAN ECONOMIC REVIEW DECEMBER 2001

icant. This difference is due to the fact that
McArthur and Sachs include Britain and France
in their sample. Britain and France are not in
our sample, which consists of only ex-colonies
(there is no reason for variation in the mortality
rates of British and French troops at home to be
related to their institutional development). It
turns out that once Britain and France are left
out, the McArthur and Sachs’ specification gen-
erates no evidence that geography/health vari-
ables have an important effect on economic
performance.29
As a final strategy to see whether settler mor-
tality could be proxying for the current disease
environment, we estimated models using a
yellow fever instrument. This is a dummy vari-
able indicating whether the area was ever af-
fected by yellow fever (from Oldstone, 1998;
see Appendix Table A1). This is an attractive
alternative strategy because yellow fever is
mostly eradicated today, so this dummy should
not be correlated with the current disease envi-
ronment. The disadvantage of this approach is
that there is less variation in this instrument than
our settler mortality variable. Despite this, the
yellow fever results, reported in columns (10)
and (11) of Table 7, are encouraging. The esti-
mate in our base sample is 0.91 (s.e. 5 0.24)
comparable to our baseline estimate of 0.95
reported in Table 4. Adding continent dummies
in column (11) reduces this estimate slightly to
0.90 (s.e. 5 0.32).30
B. Overidentification Tests
We can also investigate the validity of our
approach by using overidentification tests. Ac-
cording to our theory, settler mortality (M) af-
fected settlements (S); settlements affected
early institutions (C); and early institutions af-
fected current institutions (R)—cf., equations
(2), (3), and (4). We can test whether any of
these variables, C, S, and M, has a direct effect
on income per capita, log y, by using measures
of C and S as additional instruments. The overi-
dentification test presumes that one of these
instruments, say S, is truly exogenous, and tests
for the exogeneity of the others, such as settler
mortality. This approach is useful since it is a
direct test of our exclusion restriction. However,
such tests may not lead to a rejection if all
instruments are invalid, but still highly corre-
lated with each other. Therefore, the results
have to be interpreted with caution.
Overall, the overidentification test will reject
the validity of our approach if either (i) the
equation of interest, (1), does not have a con-
stant coefficient, i.e., log yi 5 m 1 aiRi 1 «i ,
where i denotes country, or (ii) C or S has a
direct effect on income per capita, log yi (i.e.,
either S or C is correlated with «i), or (iii)
settler mortality, M, has an effect on log yi that
works through another variable, such as culture.
The data support the overidentifying restric-
tions implied by our approach.31 This implies
that, subject to the usual problems of power
associated with overidentification tests, we can
rule out all three of the above possibilities. This
gives us additional confidence that settler mor-
tality is a valid instrument and that we are
estimating the effect of institutions on current
performance with our instrumental-variable
strategy (i.e., not capturing the effect of omitted
variables).
29 McArthur and Sachs (2001) also report specifications
with more instruments. However, using six or seven instru-
ments with only 64 observations leads to the “too-many-
instruments” problem, typically biasing the IV estimate
towards the OLS estimate (see John Bound et al., 1995). We
therefore did not pursue these estimates further.
Finally, McArthur and Sachs also argue that our ex-
colonies sample may not have enough geographic variation.
In their view, this may be why we do not find a role for
geographic variables. Nonetheless, there is substantial vari-
ation in the geography variables in our sample which in-
cludes countries such as Canada, the United States, New
Zealand, and Australia. The standard deviation of distance
from the equator in the world is 1.89, greater than 1.33 in
our sample. This is mainly because there are a large number
of European countries with high latitudes in the world
sample, but not in our sample.
30 If we drop the Neo-Europes (not reported here), the
estimate is still similar and highly significant, 1.05 (s.e. 5
0.35).
31 In some specifications, the overidentification tests us-
ing measures of early institutions reject at that 10-percent
level (but not at the 5-percent level). There are in fact good
reasons to expect institutions circa 1900 to have a direct
effect on income today (and hence the overidentifying tests
to reject our restrictions): these institutions should affect
physical and human capital investments at the beginning of
the century, and have some effect on current income levels
through this channel.
1393VOL. 91 NO. 5 ACEMOGLU ET AL.: THE COLONIAL ORIGINS OF DEVELOPMENT

The results of the overidentification tests,
and related results, are reported in Table 8. In
the top panel, Panel A, we report the 2SLS
estimates of the effect of protection against
expropriation on GDP per capita using a va-
riety of instruments other than mortality rates,
while Panel B gives the corresponding first
stages. These estimates are always quite close
to those reported in Table 4. For example, in
column (1), we use European settlements in
1900 as the only instrument for institutions.
This results in an estimated effect of 0.87
(with standard error 0.14), as compared to our
baseline estimate of 0.94. The other columns
add latitude, and use other instruments such
as constraint on the executive in 1900 and in
the first year of independence, and democracy
in 1900.
Panel D reports an easy-to-interpret version
of the overidentification test. It adds the log of
mortality as an exogenous regressor. If mor-
tality rates faced by settlers had a direct effect
on income per capita, we would expect this
variable to come in negative and significant.
In all cases, it is small and statistically insig-
nificant. For example, in column (1), log mor-
tality has a coefficient of 20.07 (with
standard error 0.17). This confirms that the
TABLE 8—OVERIDENTIFICATION TESTS
Base
sample
(1)
Base
sample
(2)
Base
sample
(3)
Base
sample
(4)
Base
sample
(5)
Base
sample
(6)
Base
sample
(7)
Base
sample
(8)
Base
sample
(9)
Base
sample
(10)
Panel A: Two-Stage Least Squares
Average protection against expropriation 0.87 0.92 0.71 0.68 0.72 0.69 0.60 0.61 0.55 0.56
risk, 1985–1995 (0.14) (0.20) (0.15) (0.20) (0.14) (0.19) (0.14) (0.17) (0.12) (0.14)
Latitude 20.47 20.34 0.31 20.41 20.16
(1.20) (1.10) (1.05) (0.92) (0.81)
Panel B: First Stage for Average Protection Against Expropriation Risk
European settlements in 1900 3.20 2.90
(0.62) (0.83)
Constraint on executive in 1900 0.32 0.26
(0.08) (0.09)
Democracy in 1900 0.24 0.20
(0.06) (0.07)
Constraint on executive in first year of 0.25 0.22
independence (0.08) (0.08)
Democracy in first year of independence 0.19 0.17
(0.05) (0.05)
R2 0.30 0.30 0.20 0.24 0.24 0.26 0.19 0.25 0.26 0.30
Panel C: Results from Overidentification Test
p-value (from chi-squared test) [0.67] [0.96] [0.09] [0.20] [0.11] [0.28] [0.67] [0.79] [0.22] [0.26]
Panel D: Second Stage with Log Mortality as Exogenous Variable
Average protection against expropriation 0.81 0.88 0.45 0.42 0.52 0.48 0.49 0.49 0.4 0.41
risk, 1985–1995 (0.23) (0.30) (0.25) (0.30) (0.23) (0.28) (0.23) (0.25) (0.18) (0.19)
Log European settler mortality 20.07 20.05 20.25 20.26 20.21 20.22 20.14 20.14 20.19 20.19
(0.17) (0.18) (0.16) (0.17) (0.15) (0.16) (0.16) (0.15) (0.13) (0.12)
Latitude 20.52 0.38 0.28 20.38 20.17
(1.15) (0.89) (0.86) (0.84) (0.73)
Notes: Panel A reports the two-stage least-squares estimates with log GDP per capita (PPP basis) in 1995 as the dependent variable, and Panel
B reports the corresponding first stage (latitude is included in even-numbered columns but is never significant and not reported here to save
space). Panel C reports the p-value for the null hypothesis that the coefficient on average protection against expropriation risk in the
second-stage regression (i.e., Panel A) is the same as when instrumented using log mortality of settlers in addition to the indicated instruments.
Panel D reports results from the regression in which log mortality is included as an exogenous variable and current institutions are instrumented
using the alternative instrument indicated. Standard errors are in parentheses. All regressions with constraint on executive and democracy in
first year of independence also include years since independence as a regressor. All regressions have 60 observations, except those with
democracy in 1900 which have 59 observations and those with European settlements in 1900 which have 63 observations.
1394 THE AMERICAN ECONOMIC REVIEW DECEMBER 2001

impact of mortality rates faced by settlers
likely works through their effect on
institutions.
Finally, for completeness, in Panel C we re-
port the p-value from the appropriate x2 overi-
dentification test. This tests whether the 2SLS
coefficients estimated with the instruments in-
dicated in Panels A and B versus the coeffi-
cients estimated using (log) settler mortality in
addition to the “true” instruments are signifi-
cantly different (e.g., in the first column, the
coefficient using European settlements alone is
compared to the estimate using European set-
tlements and log mortality as instruments). We
never reject the hypothesis that they are equal at
the 5-percent significance level. So these results
also show no evidence that mortality rates faced
by settlers have a direct effect—or an effect
working through a variable other than institu-
tions—on income per capita.
VI. Concluding Remarks
Many economists and social scientists be-
lieve that differences in institutions and state
policies are at the root of large differences in
income per capita across countries. There is
little agreement, however, about what deter-
mines institutions and government attitudes to-
wards economic progress, making it difficult to
isolate exogenous sources of variation in insti-
tutions to estimate their effect on performance.
In this paper we argued that differences in co-
lonial experience could be a source of exoge-
nous differences in institutions.
Our argument rests on the following pre-
mises: (1) Europeans adopted very different col-
onization strategies, with different associated
institutions. In one extreme, as in the case of the
United States, Australia, and New Zealand, they
went and settled in the colonies and set up
institutions that enforced the rule of law and
encouraged investment. In the other extreme, as
in the Congo or the Gold Coast, they set up
extractive states with the intention of transfer-
ring resources rapidly to the metropole. These
institutions were detrimental to investment and
economic progress. (2) The colonization strat-
egy was in part determined by the feasibility of
European settlement. In places where Europe-
ans faced very high mortality rates, they could
not go and settle, and they were more likely to
set up extractive states. (3) Finally, we argue
that these early institutions persisted to the
present. Determinants of whether Europeans
could go and settle in the colonies, therefore,
have an important effect on institutions today.
We exploit these differences as a source of
exogenous variation to estimate the impact of
institutions on economic performance.
There is a high correlation between mortality
rates faced by soldiers, bishops, and sailors in
the colonies and European settlements; between
European settlements and early measures of in-
stitutions; and between early institutions and
institutions today. We estimate large effects of
institutions on income per capita using this
source of variation. We also document that this
relationship is not driven by outliers, and is
robust to controlling for latitude, climate, cur-
rent disease environment, religion, natural
resources, soil quality, ethnolinguistic fragmen-
tation, and current racial composition.
It is useful to point out that our findings do
not imply that institutions today are predeter-
mined by colonial policies and cannot be
changed. We emphasize colonial experience as
one of the many factors affecting institutions.
Since mortality rates faced by settlers are argu-
ably exogenous, they are useful as an instru-
ment to isolate the effect of institutions on
performance. In fact, our reading is that these
results suggest substantial economic gains from
improving institutions, for example as in the
case of Japan during the Meiji Restoration or
South Korea during the 1960’s.
There are many questions that our analysis
does not address. Institutions are treated largely
as a “black box”: The results indicate that re-
ducing expropriation risk (or improving other
aspects of the “cluster of institutions”) would
result in significant gains in income per capita,
but do not point out what concrete steps would
lead to an improvement in these institutions.
Institutional features, such as expropriation risk,
property rights enforcement, or rule of law,
should probably be interpreted as an equilib-
rium outcome, related to some more funda-
mental “institutions,” e.g., presidential versus
parliamentary system, which can be changed
directly. A more detailed analysis of the effect
of more fundamental institutions on property
1395VOL. 91 NO. 5 ACEMOGLU ET AL.: THE COLONIAL ORIGINS OF DEVELOPMENT

rights and expropriation risk is an important
area for future study.
APPENDIX A: BIAS IN THE EFFECT OF
INSTITUTIONS WHEN OTHER ENDOGENOUS
VARIABLES ARE INCLUDED
To simplify notation, suppose that Ri is ex-
ogenous, and another variable that is endoge-
nous, zi , such as prevalence of malaria or
ethnolinguistic fragmentation, is added to the
regression. Then, the simultaneous equations
model becomes
Yi 5 m0 1 aRi 1 pzi 1 « i
zi 5 m1 1 fYi 1 h i ,
where Yi 5 log yi. We presume that a $ 0, f ,
0, and p , 0, which implies that we interpret zi
as a negative influence on income. Moreover,
this naturally implies that cov(hi , «i) , 0 and
cov( zi , Ri) , 0, that is, the factor zi is likely to
be negatively correlated with positive influ-
ences on income.
Standard arguments imply that
plim aˆ 5 a 1
cov~R˜ i , «i !
var~R˜ i !
5 a 2 k z
cov~zi , «i !
var~R˜ i !
,
where k and R˜ i are the coefficient and the
residual from the auxiliary equation, Ri 5 k0 1
kzi 1 R˜ i , and so k 5 cov( zi , Ri)/var( zi) ,
0, which is negative due to the fact that cov(Ri ,
zi) , 0. The reduced form for zi is:
(A1) zi 5
1
1 2 fp ~~m 1 fp!
1 faRi 1 f« i 1 h i !.
We impose the regularity condition f z p , 1,
so that an increase in the disturbance to the
z-equation, hi , actually increases zi. Now using
this reduced form, we can write
(A2) plim aˆ 5 a 2 k z cov~zi , «i !
var~R˜ i !
5 a 2 k z
~s
«h
1 fs
«
2
!
~1 2 fp! z var~R˜ i !
where s
«
2 is the variance of «, and s
«h
is the
covariance of « and h.
Substituting for k in (A2), we obtain:
plim aˆ
5 a 2
~s
«h
1 fs
«
2
!
~1 2 fp! z var~R˜ i !
z
cov~zi , Ri !
var~zi !
.
Recall that f , 0, s
«h
, 0, and cov( zi , Ri) ,
0. Therefore, plim aˆ , a, and when we control
for the endogenous variable zi , the coefficient
on our institution variable will be biased
downwards.
1396 THE AMERICAN ECONOMIC REVIEW DECEMBER 2001

APPENDIX TABLE A2—DATA ON MORTALITY
Former colonies
Abbreviated
name used
in graphs
Log GDP
per capita
(PPP) in
1995
Average
protection
against
expropriation
risk
1985–1995
Main
mortality
estimate Former colonies
Abbreviated
name used
in graphs
Log GDP
per capita
(PPP) in
1995
Average
protection
against
expropriation
risk
1985–1995
Main
mortality
estimate
Algeria DZA 8.39 6.50 78.2 Jamaica JAM 8.19 7.09 130
Angola AGO 7.77 5.36 280 Kenya KEN 7.06 6.05 145
Argentina ARG 9.13 6.39 68.9 Madagascar MDG 6.84 4.45 536.04
Australia AUS 9.90 9.32 8.55 Malaysia MYS 8.89 7.95 17.7
Bahamas BHS 9.29 7.50 85 Mali MLI 6.57 4.00 2940
Bangladesh BGD 6.88 5.14 71.41 Malta MLT 9.43 7.23 16.3
Bolivia BOL 7.93 5.64 71 Mexico MEX 8.94 7.50 71
Brazil BRA 8.73 7.91 71 Morocco MAR 8.04 7.09 78.2
Burkina Faso BFA 6.85 4.45 280 New Zealand NZL 9.76 9.73 8.55
Cameroon CMR 7.50 6.45 280 Nicaragua NIC 7.54 5.23 163.3
Canada CAN 9.99 9.73 16.1 Niger NER 6.73 5.00 400
Chile CHL 9.34 7.82 68.9 Nigeria NGA 6.81 5.55 2004
Colombia COL 8.81 7.32 71 Pakistan PAK 7.35 6.05 36.99
Congo (Brazzaville) COG 7.42 4.68 240 Panama PAN 8.84 5.91 163.3
Costa Rica CRI 8.79 7.05 78.1 Paraguay PRY 8.21 6.95 78.1
Coˆte d’Ivoire CIV 7.44 7.00 668 Peru PER 8.40 5.77 71
Dominican Republic DOM 8.36 6.18 130 Senegal SEN 7.40 6.00 164.66
Ecuador ECU 8.47 6.55 71 Sierra Leone SLE 6.25 5.82 483
Egypt EGY 7.95 6.77 67.8 Singapore SGP 10.15 9.32 17.7
El Salvador SLV 7.95 5.00 78.1 South Africa ZAF 8.89 6.86 15.5
Ethiopia ETH 6.11 5.73 26 Sri Lanka LKA 7.73 6.05 69.8
Gabon GAB 8.90 7.82 280 Sudan SDN 7.31 4.00 88.2
Gambia GMB 7.27 8.27 1470 Tanzania TZA 6.25 6.64 145
Ghana GHA 7.37 6.27 668 Togo TGO 7.22 6.91 668
Guatemala GTM 8.29 5.14 71 Trinidad and Tobago TTO 8.77 7.45 85
Guinea GIN 7.49 6.55 483 Tunisia TUN 8.48 6.45 63
Guyana GUY 7.90 5.89 32.18 Uganda UGA 6.97 4.45 280
Haiti HTI 7.15 3.73 130 Uruguay URY 9.03 7.00 71
Honduras HND 7.69 5.32 78.1 USA USA 10.22 10.00 15
Hong Kong HKG 10.05 8.14 14.9 Venezuela VEN 9.07 7.14 78.1
India IND 7.33 8.27 48.63 Vietnam VNM 7.28 6.41 140
Indonesia IDN 8.07 7.59 170 Zaire ZAR 6.87 3.50 240
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