The impact of education on political ideology: Evidence from European compulsory education reforms

•I estimate the causal effect of educational attainment on political ideology.•Changes in compulsory education laws provide the needed exogenous variation.•An extra year of education moves individuals to the right on average.•I also find some evidence of no effect for a subgroup of countries.•These European results are most consistent with the self-interest thesis.

Previous research documents a correlation between education and political ideology, usually indicating a positive relationship between education and left-wing political views. In this paper, I examine to what extent this association is causal. I merge political ideology data from 25 waves of Eurobarometer surveys with information on 18 educational reforms in 11 European countries. I then instrument for educational attainment with a regression discontinuity design that estimates the increase in education due to compulsory educational reforms. Notably, it appears that omitted variables bias is important here. I find a significant causal effect of education moving individuals to the right when properly addressing the endogeneity whereas there is a significant association between education and left-wing political ideology when treating education as exogenous. I find that on average, among the individuals compelled into additional education from these specific reforms, an additional year of education moves individuals to the right of the political continuum by about 5-6%. However, I also find no evidence of a causal effect on political ideology for a subgroup of countries.