A comparison of different methods for decomposition of changes in expectation of life at birth and differentials in life expectancy at birth

Abstract

Several methods have been proposed to decompose the difference between two life expectancies at birth into the contributions of diverse age groups. This study attempts to compare the system adopted by Chandra Sekar (1949) with various other methodologies such as those suggested by Arriaga, Lopez and Ruzicka and Pollard. The aim is to show that all these techniques in their modified (symmetrical) form will produce the same result as that of United Nations, Pollard, Andreev and Pressat. Finally, this study suggests that the symmetric formulae the above methods be used to arrive at near precise results since the percentage contribution of the sum of interaction terms with respect to difference in the life expectancy at birth is found to negligible. © 2005 Max-Planck-Gesellschaft.