Many scholars have analysed compulsory voting effects on inequality of turnout or even policy outcomes. However, its relationship with political polarization has not been addressed yet, despite frequent claims (including by high officials) that where turnout is optional extremists are more prone to vote.

This paper fills this gap, providing evidence with survey data, mainly from the Comparative Study of Electoral Systems (CSES), on whether the of proportion of centrist voters (as compared to those that place themselves closer to the bounds of the 0-10 Left-Right scale) is higher in countries with compulsory vote.

Although this is not, per se, an evidence of effects of compulsory/facultative vote in the ideological distribution of a country as a whole, understanding if there is an effect on polls could help explaining the vicious circles of polarization (where extremist voters elect extremist representatives, leading to political disaffection, hence more polarization among voters). It is also important to feed the frequent debates in many countries about changing from compulsory to facultative or vice-versa.