Isolating Age, Period, and Cohort Effects in Developmental Research

Abstract

Separating age, period, and cohort effects in developmental research is complicated by their linear dependence. Differing approaches have been advanced to address this problem. These approaches generally presume that age, period, and cohort are conceptually discrete entities; that is, they are confounded statistically, but not logically. This article outlines the dilemma, reviews solutions that have been advanced, and critically examines the assumptions on which these solutions are based.