EDUCATIONAL PSYCHOLOGIST, 42(2), 99–107
Copyright
C©
2007, Lawrence Erlbaum Associates, Inc.
Scaffolding and Achievement in Problem-Based and Inquiry Learning:
A Response to Kirschner, Sweller, and Clark (2006)
Cindy E. Hmelo-Silver, Ravit Golan Duncan, and Clark A. Chinn
Department of Educational Psychology
Rutgers University
Many innovative approaches to education such as problem-based learning (PBL) and inquiry
learning (IL) situate learning in problem-solving or investigations of complex phenomena.
Kirschner, Sweller, and Clark (2006) grouped these approaches together with unguided discov-
ery learning. However, the problem with their line of argument is that IL and PBL approaches
are highly scaffolded. In this article, we first demonstrate that Kirschner et al. have mistakenly
conflated PBL and IL with discovery learning. We then present evidence demonstrating that
PBL and IL are powerful and effective models of learning. Far from being contrary to many
of the principles of guided learning that Kirschner et al. discussed, both PBL and IL employ
scaffolding extensively thereby reducing the cognitive load and allowing students to learn in
complex domains. Moreover, these approaches to learning address important goals of educa-
tion that include content knowledge, epistemic practices, and soft skills such as collaboration
and self-directed learning.
WHY PROBLEM-BASED AND INQUIRY
LEARNING ARE NOT MINIMALLY GUIDED:
ON ASSUMPTIONS AND EVIDENCE
All learning involves knowledge construction in one form or
another; it is therefore a constructivist process. The question
of what sorts of instructional practices are likely to promote
such knowledge construction, or learning, is at the core of the
argument presented by Kirschner, Sweller, and Clark (2006).
The authors loosely define minimally guided instruction as
a learning context in which “learners, rather than being pre-
sented with essential information, must discover or construct
essential information for themselves” (p. 1). They conversely
define direct guidance instruction as “providing information
that fully explains the concepts and procedures that students
are required to learn.” In their argument, Kirschner et al.
contrast minimally guided instructional approaches with ap-
proaches that provide direct instructional guidance and assert
that minimally guided instructional approaches are ineffec-
tive and inefficient.
Correspondence should be addressed to Cindy E. Hmelo-Silver, Depart-
ment of Educational Psychology, Rutgers University, 10 Seminary Place,
New Brunswick, NJ 08901-1183. E-mail: chmelo@rci.rutgers.edu
There are twomajor flaws with Kirschner et al’s argument.
The first is a pedagogical one. Kirschner and colleagues have
indiscriminately lumped together several distinct pedagog-
ical approaches—constructivist, discovery, problem-based,
experiential, and inquiry-based—under the category of min-
imally guided instruction. We argue here that at least some
of these approaches, in particular, problem-based learning
(PBL) and inquiry learning (IL), are not minimally guided
instructional approaches but rather provide extensive scaf-
folding and guidance to facilitate student learning.
The second is a flaw in their evidentiary base. The claim
by Kirschner et al. that approaches such as PBL and IL
are ineffective is contrary to empirical evidence that indeed
does support the efficacy of PBL and IL as instructional
approaches. This evidence suggests that these approaches
can foster deep andmeaningful learning as well as significant
gains in student achievement on standardized tests.
In our article we will discuss how PBL and IL provide
instructional guidance and provide evidence that supports
the efficacy of these pedagogical approaches. We will exam-
ine the claims of Kirschner et al. specifically in the context
of PBL and IL, as these approaches clearly provide scaf-
folding for student learning. We begin with a brief discus-
sion of the qualities of some of the pedagogical approaches

100 HMELO-SILVER, DUNCAN, CHINN
Kirschner et al. have included under their “minimally guided”
umbrella.
ARE PBL AND IL INSTANCES OF MINIMALLY
GUIDED INSTRUCTION?
Constructivist theories of learning stress the importance of
learners being engaged in constructing their own knowledge
(Mayer, 2004; Palincsar, 1998). An assumption that leads to
the minimally guided discovery approach is that the learn-
ers need to explore phenomena and/or problems without any
guidance. This assumption has been repeatedly demonstrated
to be flawed (Mayer, 2004). We agree with Kirschner et al.
(2006) that there is little evidence to suggest that unguided
and experientially-based approaches foster learning. How-
ever, IL and PBL are not discovery approaches and are not
instances of minimally guided instruction, contrary to the
claims of Kirschner et al. Rather, PBL and IL provide con-
siderable guidance to students.
Before we discuss the ways in which PBL and IL are not
minimally guided, we begin by clarifying what is meant by
PBL and IL. In PBL, students learn content, strategies, and
self-directed learning skills through collaboratively solving
problems, reflecting on their experiences, and engaging in
self-directed inquiry. In IL, students learn content as well
as discipline-specific reasoning skills and practices (often in
scientific disciplines) by collaboratively engaging in investi-
gations. Both PBL and IL are organized around relevant, au-
thentic problems or questions. Both place heavy emphasis on
collaborative learning and activity. In both, students are cog-
nitively engaged in sensemaking, developing evidence-based
explanations, and communicating their ideas. The teacher
plays a key role in facilitating the learning process and may
provide content knowledge on a just-in-time basis.
The major distinction that we perceive between PBL and
IL is their origins. PBL has its origins in medical education
and is based on research on medical expertise that empha-
sized a hypothetical-deductive reasoning process (Barrows
& Tamblyn, 1980). PBL often uses text-based resources for
both the problem data and self-directed learning. IL has its
origins in the practices of scientific inquiry and places a heavy
emphasis on posing questions, gathering and analyzing data,
and constructing evidence-based arguments (Kuhn, Black,
Keselman, & Kaplan, 2000; Krajcik & Blumenfeld, 2006).
As we have examined the broad variety of instantiations of
PBL and IL, we have not uncovered any dimensions that con-
sistently distinguish between PBL and IL. Indeed, we think
there are no clear-cut distinguishing features. PBL frequently
engages students in explorations and analyses of data, such
as one would expect IL environments to do, and IL frequently
poses problems and asks students to consult various resources
to solve them as PBL environments do. For example, prob-
lems in medical PBL present students with rich sets of pa-
tient data to analyze (Barrows, 2000; Hmelo-Silver, 2004).
Similarly, IL environments such as the Web Integrated Sci-
ence Environment (WISE) provide students with scientific
problems and the research materials that students examine
in order to reach a conclusion about the problem (Linn &
Slotta, 2006). Students may read a variety of resources in ad-
dition to reading about data and conducting their own studies.
Thus, in practice PBL and IL environments are often indis-
tinguishable, despite divergent origins and so we treat them
as synonymous in this article.
As we have noted, PBL and IL environments are not mini-
mally guided because ofmany forms of scaffolding provided.
Moreover, these approaches may include direct instruction
as one of the strategies they employ (Krajcik, Czerniak, &
Berger, 1999; Schmidt, 1983; Schwartz & Bransford, 1998).
However, in these contexts, direct instruction may be pro-
vided on a just-in-time basis and generally once students ex-
perience a need to know the information presented (Edelson,
2001). Thus a mini-lecture or benchmark lesson presenting
key information to students is used when students understand
the necessity of that information and its relevance to their
problem-solving and investigational practices. Such just-in-
time direct instruction promotes knowledge construction in a
way that makes knowledge available for future use in relevant
contexts (Edelson, 2001).
There is an extensive body of research on scaffold-
ing learning in inquiry- and problem based environments
(Collins, Brown, & Newman, 1989; Davis & Linn, 2000;
Golan, Kyza, Reiser, & Edelson, 2002; Guzdial, 1994; Jack-
son, Stratford, Krajcik, & Soloway, 1994; Reiser, 2004; Toth,
Suthers, & Lesgold, 2002), and researchers have developed
theory-driven and empirically based design guidelines for in-
corporating effective scaffolding strategies to support learn-
ing (Hmelo & Guzdial, 1996; Hmelo-Silver, 2006; Quintana
et al., 2004; Reiser et al., 2001).
Scaffolded inquiry and problem-based environments
present learners with opportunities to engage in complex
tasks that would otherwise be beyond their current abilities.
Scaffolding makes the learning more tractable for students
by changing complex and difficult tasks in ways that make
these tasks accessible, manageable, and within student’s zone
of proximal development (Rogoff, 1990; Vygotsky, 1978).
Quintana et al. (2004) conceived of scaffolding as a key ele-
ment of cognitive apprenticeship, whereby students become
increasingly accomplished problem-solvers given structure
and guidance from mentors who scaffold students through
coaching, task structuring, and hints, without explicitly giv-
ing students the final answers. An important feature of scaf-
folding is that it supports students’ learning of both how to
do the task as well as why the task should be done that way
(Hmelo-Silver, 2006).
Scaffolding not only guides learners through the complex-
ities of the task, it may also problematize important aspects
of students’ work in order to force them to engage with key
disciplinary frameworks and strategies (Reiser, 2004). Such
scaffolds act by “rocking the boat” and stopping mindless