Terminology and Basic Rules of Electoral Systems

This chapter argues that current categorizations of electoral systems retain some utility but should be re-thought to capture recent advances in scholarship on electoral systems. A rigid categorical division between proportional and plurality systems should be replaced with a more sophisticated understanding of electoral systems on a continuum, and the use of the Seat Product Model. The chapter also develops an agenda of specific terminological usage, which will be employed throughout the Oxford Handbook of Electoral Systems and which the authors advocate for field-wide adoption. Finally, the chapter reviews the contributions of the chapters in the volume and places them in perspective.

Electoral Systems and Issue Polarization

This chapter reviews theoretical and empirical research pertaining to the question: How do electoral systems influence parties’ programmatic incentives, that is, the policy positions party elites present to the public? More specifically, it discusses whether electoral systems influence the diversity of party policy positions, measured via the degree of party system polarization. It emphasizes electoral laws’ permissiveness or proportionality, defined in terms of the relationship between parties’ national vote shares and their share of parliamentary seats. The review of theoretical arguments suggests that any effects of proportionality on polarization should be modest, a prediction supported by empirical studies that identify only weak and inconsistent relationships between proportionality and party polarization along the left–right ideological dimension.

Electoral Systems in Context

Italy stands out among advanced industrialized democracies because of its frequency of major electoral reforms. In the postwar period, Italy has experienced four major electoral systems: the proportional representation (PR) system of the First Republic (1948–1992), mixed-member majoritarian (MMM, 1993–2005), and two varieties of PR with majority bonus (2005–2015, 2015–). In addition, there have been many failed attempts at electoral reform through legislation or referendum. The frequency of electoral reform makes Italy an important case for investigating the causes and effects of electoral system change. However, the path to each change has been somewhat idiosyncratic: the major reform of 1993 came against the backdrop of revelations of massive corruption, while the 2005 reform can be understood as an attempt to engineer divided government by an incumbent coalition expecting losses in the next election. The effects of the electoral reforms have also not always been as expected.

Dimensions of Variation in Electoral Systems

Electoral systems matter. They are a crucial link in the chain connecting the preferences of citizens to the policy choices made by governments. They are chosen by political actors and, once in existence, have political consequences for those actors. This chapter argues that electoral system choice is a highly consequential matter for democratic states and offers a comparative overview of the principal means by which electoral systems vary. What are the essential components of real-world electoral systems? The chapter emphasizes the importance of district magnitude, ballot structure (with three main types: categorical, dividual, and ordinal), “levels” of seat allocation, methods of selecting candidates within parties, and devices for limiting proportionality.

Experimental Research Design in the Study of Electoral Systems

Understanding the effects of electoral systems is of great importance to both scholars and practitioners, and experimental research can be a valuable tool in pursuit of this goal. However, scholars need to think carefully about how to utilize experimental research, especially because the variation in electoral systems in which we are most interested—at the national level—is often impossible or unethical to manipulate. To inform how experiments and related methods of causal inference are then still able to facilitate investigations into the roots and consequences of electoral systems, we situate experimental research within a broader account of research design in the study of electoral systems, summarize existing experimental work, and discuss future avenues. We call for carefully crafting experimental tests in the laboratory and for using “naturally” occurring variation in existing institutions at lower levels of the electoral system.

Electoral Systems in Context

Colombia represents a rare case of a political context with a number of electoral system changes over a period of years. It serves as a natural experiment that demonstrates that party systems do react to changes in institutional parameters. There have been uninterrupted democratic elections that allow for long-term comparative study of the effects of electoral reform. From 1974 to 2014, several different basic electoral rules can be observed including single nontransferable vote (SNTV), and the D’Hondt form of party-list proportional representation. Additionally, other factors have changed including a major shift in district magnitude for the election of the Senate, a move from plurality to a two-round system for electing the president, and other areas of change including ballot format and open versus closed lists. Few cases demonstrate as many different areas of electoral study as does Colombia.

Electoral Systems in Context

The Republic of Ireland is unusual in using the single transferable vote to elect its national parliament. The system allows voters to rank candidates in order of preference, and those lower preferences are used to allocate seats when a count of first preferences shows that candidates have no overall majority or, in multiseat elections, do not reach a set quota. The party system showed little fragmentation until recently, and proportionality has been only a little less than in many proportional representation systems. The public twice rejected moves to change the system and continues to express satisfaction with the control it appears to give them over their representatives, despite the criticisms expressed by many politicians and commentators.

Electoral Systems in Context

South Africa’s post-apartheid election outcomes demonstrate how contextual factors interact with electoral rules to shape party systems. South Africa’s national electoral system represents one of the most permissive in the world, combining parliamentary rules with an extreme form of proportional representation. These rules were selected to encourage broad representation of parties in the National Assembly. However, South Africa’s party system consistently defies expectations, with a low effective number of seat-winning parties at the national level and dominance by a single party, the African National Congress (ANC). Provincial and municipal outcomes also confound simple institutional expectations. In addition to describing electoral rules and party systems at all three levels of South Africa’s political system, this chapter argues that contextual factors like the salience of racial divisions and the ability of the ruling party to shape institutions and resource flows critically interact with electoral institutions to shape party system outcomes.

Electoral Systems in Context

Overall, elections in France take place in a two-round system (with the exception of the European elections), and although each different electoral arena has its own particular procedures, most promote majoritarian principles. This chapter analyzes the electoral system of the French Fifth Republic by focusing on the operation of these rules in the larger political context: including the interaction between the rules, the party system, and the main political actors that compete in them. It shows that the two-round majoritarian system has proven remarkably stable and has managed to survive both internal (a quick detour to proportional representation in 1986) and external challenges (rise of new parties, EU common rules on proportional representation).

Electoral System Change

Most research into electoral systems focuses on their effects. Only recently has a significant literature emerged examining how they are chosen. This chapter explores four core issues in that literature. First, it considers what is meant by “electoral system change.” This can refer to changes of any scale to any electoral rules in any context, but typically—including here—a narrower definition is used. Second, the chapter investigates what electoral system changes happen. It considers the frequency of reforms and patterns in those reforms. Third, it examines the determinants of electoral system change. Most studies focus on the microfoundations of reform. Others highlight the systemic level. Both perspectives are needed to develop a complete picture. Finally, the chapter gauges the effects of electoral system change and assesses why such changes, notwithstanding important effects, often fail to deliver on their promoters’ expectations.