Measuring de facto versus de iure political institutions in the long-run: a multivariate statistical approach

In this paper we use the components of the PolityIV project’s polity2 and Vanhanen’s Index of Democracy indicators to analyse the relationship between de iure and de facto political institutions from 1820 until 2000 with a canonical correlation method, and a correction for the sample selection bias, caused by the change in the number of available countries. We find considerably fluctuation in the relationship between the two measures and that much of the observed correlation is due to the sample selection bias. The relationship becomes strong and positive only in the second half of the 20th century.