Age, period and cohort analysis in a comparative context: Political generations and political participation repertoires in Western Europe

• Method to study age-period-cohort effects in a comparative context (Western Europe).
• Multi-level models with random coefficients.
• Application of GAMs and GAMMs to plot shape of cohort effects.
• Tests if generations differ in participation patterns based on era of socialization.
• Tests if ascendancy of repertoires in eras of socialization relates to differences.

This paper presents a method for studying age-period-cohort effects in a comparative context where repeated cross-sectional data are available covering a suitably long period of time. The method consists in the application of multi-level models with country as the higher level of analysis and random coefficients to model variables which vary at the country-level. Additionally, the application of generalized additive models (GAMs) and generalized additive mixed models (GAMMs) provides robust empirical tests of cohort categorizations applied in this and previous studies to estimate otherwise collinear effects. To illustrate the method, I derive and test the theory that generations will be differentiated in their patterns of participation based on the ascendancy of certain repertoires in the era of their political socialization.