Electoral institutions, malapportionment and the representation of ethnic minorities

The representation of ethnic minorities in national legislatures varies widely: in some cases minorities are privileged through ethnic reserved seats or territorial concentration, while in others they remain systematically excluded. Electoral institutions have been largely shown to help explain these patterns, yet one mechanism has received little comparative attention: malapportionment – the imbalance between the distribution of seats and votes across districts. Despite its relevance, research has been limited by the empirical difficulty of linking electoral outcomes with the territorial distribution of ethnic groups. This paper addresses this gap by introducing a novel cross-national dataset covering more than 22,000 legislative districts in 84 countries (1996–2020) in lower-house elections, which for the first time identifies, at the district level, the presence of ethnic minorities excluded from executive power. Our empirical analyses show that countries with ethnic reserved seats for minorities tend to exhibit higher malapportionment, and that minority-concentrated districts are more often over-represented. We also find that over-representation is most pronounced in open autocracies and weak democracies, a pattern consistent with the strategic use of electoral rules. These findings have important implications for understanding the institutional and political dynamics shaping minority representation in national legislatures.