A common argument against lowering the voting age is that young citizens are less informed about and interested in politics than older citizen. However, turnout among the youngest of eligible citizens (18-21) is usually higher than that of slightly older citizens (21-25). We hypothesize that eligibility causes interest and information-seeking behavior. Consequently, simple comparisons between younger (ineligible) and older (eligible) citizens would be flawed because of this endogeneity. We use a register-based panel survey of 3600 German adolescents to test the effect of eligibility on interest in and knowledge about politics. Knowing our respondents exact birth date we are able to estimate the causal effect of eligibility in a regression discontinuity design. We find a positive effect on political interest and knowledge across a variety of measures. Our results imply that lowering voting age may have beneficial effects because heightened interest of eligible youngsters is easier met while they still live at home and attend the school, e.g. registering them.
