Age, Cohort and Period in Life-Span Research: A Three-Way Analysis with Logically Missing Cells

A solution is shown for addressing the age x cohort x period issue in life-span research. Previous solutions have utilized only portions of the data in a given two-way layout. The proposed solution uses all data, which for at least two of the three two-way layouts involves missing cells. The method can be used for repeated measure designs, or designs in which new subjects are measured at each period. The design allows the assessment of each main effect and each two-way interaction. The hypotheses tested are explicitly shown, together with the linear models that accomplish this testing.