Electoral systems, defined as the manner in which votes cast in a general election are translated into seats in the legislature, matter because they influence key governance dimensions and dynamics. Electoral systems provide different kinds of incentives to appeal to voters in order to yield electoral pay‐offs. These systems come in many different varieties,and can have an impact on the degree of coherence and fragmentation of the party system and broader government effectiveness, as well as on public policy outcomes and the behavior and incentives of political actors.

This paper is organized around four main sections.

• Section 2 provides an overview of what electoral systems are and why they matter. The overview also stresses that electoral systems do not exist in a vacuum and that electoral effects are contingent on other structural and institutional factors as well.
• Section 3 looks at the different kinds of electoral systems that currently exist, organized around three broad families: plurality/majority systems,proportional representation systems, and mixed systems.
• Section 4 then explores the kinds of impact that electoral systems can have on different governance dimensions and dynamics. These include government effectiveness, violence and conflict, different aspects of public policy (including the provision of public goods and corruption), and electoral malpractice.
• The article concludes with a set of lessons outlined in Section 5.