In This Article Expand or collapse the "in this article" section The Origins and Impact of Proportional Representation

  • Introduction

Political Science The Origins and Impact of Proportional Representation
Alan Renwick
  • LAST REVIEWED: 12 July 2019
  • LAST MODIFIED: 27 November 2013
  • DOI: 10.1093/obo/9780199756223-0075


The label “proportional representation” (PR) refers to a broad family of electoral systems. Specifically, it refers to electoral systems that are designed to share representation out across different strands of opinion. This introduction briefly fleshes out this definition of PR and then outlines the sections to follow. An electoral system is a set of rules governing two things. The first is the nature of the votes that members of the electorate are able to cast: whether, for example, for candidates or parties or both; and whether for just one candidate or party or more than one. The second is the process by which these votes are tallied in order to determine who gets elected. Electoral systems can be used to elect a single person, such as a president or chair, or to elect a multimember body, such as a legislature or council. Proportional electoral systems can be used only to elect collective bodies: their purpose of sharing representation out across different strands of opinion cannot be achieved if only one person is being chosen. The systems used to elect multimember bodies can be distinguished from each other on two key dimensions: proportionality and personalization (sometimes also referred to as the “inter-party” and “intra-party” dimensions). Proportionality refers to the degree to which the seats within the multimember body are allocated in proportion to the votes won by the different groups contesting the election. PR systems can be defined as systems that generally produce close correspondence between the share of the votes won by each political party or other grouping and its share of the seats. They contrast with majoritarian systems, which tend to give significant over-representation to the largest party (or the largest two parties), while under-representing all other parties. The commonest majoritarian system is single-member plurality, also widely known as first past the post. The scale of proportionality is, however, continuous: it is possible for an electoral system to occupy any position, from highly proportional to highly disproportional. Among PR systems, the key determinant of just how proportional the system is is the number of seats allocated in each electoral district: this number is called the district magnitude. The higher the district magnitude, the closer the result can approach perfect proportionality, while the lower the district magnitude, the further the system moves from proportionality. Personalization, meanwhile, refers to the degree to which elections involve a choice not just between political parties (or other such groupings), but between individual candidates. PR systems can occupy any position on this dimension, from highly personalized to highly party-centric. Further information on the many different forms that PR can take is provided in the Varieties section below. This bibliography begins with introductory readings and an overview of key journals dealing with PR and other electoral systems. The remainder of the bibliography is then divided into three sections. The first, on Varieties, outlines literature on the many different forms that PR systems can take. The second, on Origins, examines the invention of the various forms of PR and the processes by which PR systems have been adopted—or not adopted—at different times and in different countries around the world. The third, on Effects, introduces a wide variety of literatures relating to PR’s effects. This final section is much the longest: an electoral system can have effects on many aspects of politics, and large bodies of work have emerged on each of these. The survey here addresses eight key aspects of PR’s impact.

Introductory and Reference Works

Several books provide very useful introductory overviews of this subject. In addition, a number of printed and online sources give extensive information on the electoral systems that exist and have existed around the world.

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