Many kinds of data in the social sciences have a hierarchical, multilevel or clustered structure. For example, municipalities are grouped into regions; regions are formed within countries; and quite often, countries belong to supra-national organizations. Once groupings are established, they...

This comment assesses how age, period and cohort (APC) effects are modelled with panel data in the social sciences. It considers variations on a 2-level multilevel model which has been used to show apparent evidence for simultaneous APC effects. We show that such an interpretation is often...

Vietnam experienced a dramatic drop in overall poverty during the 90s. However, the poverty reduction showed substantial variation across households, villages and regions. Using a multilevel model on panel data from the rural sample of the Vietnam Living Standard Measurement Survey we...