A cohort sequential design:

Cohort-sequential designs or accelerated longitudinal designs are designs in which adjacent segments consisting of limited longitudinal data on a specific age cohort can be linked together with similar segments from other temporally related age cohorts to determine the existence of a common developmental trend. These designs enable researchers to study individual development over a long interval of the life course by limited repeated measurements of independent age cohorts, resulting in temporally overlapping measurements of the various age groups. Such designs create possibilities not available in standard longitudinal designs for separating age effects from cohort and period effects.