Full representation (also known as proportional representation) voting systems provide representation to groupings of like-minded voters in proportion to their voting strength. If a grouping of voters -- either a political party, or a community of interest in a nonpartisan election -- wins 20 percent of the popular vote in an election for ten seats, these voters will win two of the ten seats. Sixty percent of the popular vote will win six of ten seats, and so on. Most of the world’s established democracies use some form of full representation to elect their most powerful legislative body.
Full representation voting systems facilitate the election of legislatures that more accurately represent both the ideological and demographic diversity of a population. They aim to realize the goals of majority rule and fair representation for all. There are many different variants of full representation, each with their advantages and disadvantages, as detailed in other factsheets. But all full representation systems share two attributes:
- Multi-seat districts. Full representation requires districts that elect two or more representatives to a legislature. The number of representatives per district range from two (in Chile) to more than 400 (in South Africa, where the whole country acts as a single district). Some full representation systems use a mixture of one-seat districts and multi-seat districts.
- Lower "victory threshold." Full representation systems lower the victory threshold (percentage of votes needed to win a seat) anywhere from 33 percent (in a two-seat district) to less than 1 percent. For instance, in a 3-seat district elected under full representation, a candidate needs a little more than 25% of the vote to win. By lowering the victory threshold, full representations systems facilitate fair minority representation as well as majority rule.
Beyond these two factors, however, the various full representation systems diverge, each presenting their own advantages and disadvantages. The three main categories of full representation system are Party-List Systems, Mixed-Member Systems (also known as Additional Member Systems) and Modified At-Large Voting systems, which can be used for candidate-based or nonpartisan elections.
Arguments for and against full representation systems stem from these systems’ tendency to elect legislatures that more fairly represent the range of voters in a jurisdiction. Full representation's supporters argue that this fairer representation better ensures that a legislative majority is grounded in a popular majority. It better provides for true representation of the electorate through a more accurate reflection of the demographic composition of the population, with greater representation of women, racial and political minorities and socio-economic classes than is typical in legislatures elected by winner-take-all systems. Furthermore, full representation systems tend to result in higher voter turnout, as more viable candidates run from across the political spectrum and mobilize their supporters.
Opponents of full representation argue that the fairer representation it provides in
fact can empower extremist groups, can promote single-issue candidates
and parties and can lead to unstable coalition governments in
party-based systems. They also warn against excessive influence of
party leaders (particularly in party list forms of full representation) and the dilution
of geographic representation.
(Please see relevant factsheets for in-depth discussions of the arguments for and against full representation voting systems.)