Abstract: We propose a unified approach to modeling descriptive representation that can be applied to any political body, any country, and any dimension of identity. To that end, we code the ethnic, linguistic, religious, and gender identities of nearly 65,000 elites serving in 1,807 political bodies across 156 countries. Using a summary index of representation, we then explore its causes. Our focus is on purely “compositional” (as opposed to “institutional”) factors — the size of each political body as well as the number and distribution of social groups. These are investigated through an analytical derivation of the expected representation index under random sampling of elites to bodies, with a synthetic data analysis, and with our original data on national political elites. Analyses show that half of the variability in descriptive representation across political bodies, and sixty percent of the variability across countries, is accountable to compositional factors.
Keywords: Descriptive representation; Political elites; Political institutions; Social groups