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Biology

Age-Period-Cohort Effects in Longitudinal Demographic Research

Quick fact

The 1918 influenza pandemic acted as a period effect that lifted mortality across all ages, but it also created a lasting cohort effect: the cohort born in 1919, exposed to the pandemic's aftermath, continued to show altered health and mortality patterns throughout their lives.

Why this is interesting

You may have noticed that people born in different eras think and act differently—but is that because they are different ages, because of the times they live in, or because of the generation they were born into? In demographic research, this is not merely a philosophical question, but a statistical puzzle.