Research Methods in Developmental Psychology: Longitudinal, Cross-Sectional, and Cohort Designs
Research methods in developmental psychology are not neutral technical choices made after the real thinking is done, but shape what kinds of development can be seen, what kinds of change can be inferred, and what sorts of conclusions can be drawn about age, time, experience, and the life course. This article examines cross-sectional, longitudinal, cohort, and cohort-sequential designs, along with attrition, timing, and age-period-cohort problems, as parts of one methodological framework. It argues that developmental research design should be matched to the temporal structure of the question rather than treated as a prestige marker. In that sense, methods reveal how developmental psychology thinks about change itself.









