The contingent effect of institutions: Electoral formulas, ethnic polarization, and election quality

• I explore the interaction between the electoral formula and societal heterogeneity.
• Proportional representation leads to better election quality in polarized societies.
• The electoral formula does not affect election quality in non-polarized societies.
• I identify an interactive effect between institutions and societal context.

This paper builds on existing studies linking formal electoral institutions to democracy. It reveals that there is an interactive effect between the electoral formula and the levels of ethnic polarization that systematically influences the quality of elections and the probability of government turnover. Proportional representation is associated with better elections and more frequent government turnover than single-member district majority formulas in ethnically polarized countries. However, the opposite is true when ethno-cultural groups are not numerous or polarized. This study contributes to the existing literature on formal political institutions by presenting evidence that the electoral formula's impact on governance is contingent on the context in which such institutions operate.