Electoral Systems that Delimit Electoral Districts

Traditionally, three broad categories of electoral systems have been described: plurality systems, majority systems, and proportional representation systems. The most important element that differentiates these electoral systems from one another is the means by which seats in the legislature are allocated:  

• to candidates receiving a plurality of the vote
• to candidates obtaining a majority of the vote
• proportionally on the basis of votes cast for political parties or candidates

A recent addition to these three broad categories of electoral systems is the mixed electoral system, which combines elements of both proportional representation and plurality or majority voting systems.

Delimiting Districts: Plurality or Majority Systems

The delimitation of electoral districts is most commonly associated with plurality or majority electoral systems. Both systems tend to rely heavily, if not exclusively, on single-member electoral districts. These districts must be redrawn periodically to reflect shifts in the population. Both systems also share one fundamental element because of their reliance on single-member districts--the number of seats that a political party receives depends not only on the proportion of the votes it received, but also on where those votes were cast. Under plurality and majority systems, minority political parties whose supporters are not geographically concentrated usually obtain fewer seats than their proportion of the vote would suggest they are entitled. The multimember districts of proportional systems can rectify this distortion in the transfer of votes to seats because the larger the magnitude of the electoral districts, the more proportional the results.

Delimiting Districts: Proportional Representation

There are two major types of proportional representation systems: the party list system and the single transferable vote. (The mixed member proportional system also produces proportional results, but this system will be discussed under the "mixed system" category.) The party list system is the far more common of the two. Under the party list system, electoral districts rarely, if ever, require delimitation. If electoral districts are employed, they are relatively large multimember districts whose boundaries generally correspond to administrative divisions. To accommodate shifts in population, the number of seats allocated to individual multimember districts is adjusted, rather than redrawing the boundaries of the districts. The single transferable vote, used in Ireland and Malta, is the other type of proportional representation. Because voting is on the basis of candidates, not parties, these countries employ small multimember districts with only three to five members elected per district. Electoral district boundaries must therefore be redrawn periodically in these two countries.

Delimiting Districts: Mixed Electoral Systems

Mixed electoral systems are becoming increasingly popular. They employ both party list proportional representation and single-member electoral districts with plurality or majority vote requirements. The German electoral system is the prototypical mixed electoral system.

Because mixed systems incorporate single-member districts, the delimitation of electoral districts must occur periodically to adjust for shifts in the population. The importance of the delimitation process and the influence that district configurations have on the outcome of elections is dependent on whether party list seats are used to correct any distortions in the relationship between seats to votes produced by the single-member districts. In countries such as Germany, seats allocated under the party list system are used to compensate for any distortions in the seats-to-votes ratio produced at the electoral district level. Mixed systems that use party list seats in a compensatory manner are sometimes called "mixed member proportional" systems because the election results are proportional.

In countries such as Russia, party list seats are not used to compensate for any disproportionality arising from elections in single-member districts. Rather, seats allocated to the parties under the party list component of the election are simply added to the seats won at the electoral district level. The partisan seats-to-votes ratio may therefore be distorted. In this type of mixed system, sometimes called a "parallel" system, the district delimitation process is more important because it can have a more pronounced effect on the partisan composition of the legislature.

Plurality Electoral Systems

The plurality electoral system is the oldest and the most frequently used voting system. It is used for legislative elections in the United States and India, the world's two largest liberal democracies, as well as the United Kingdom and many former British colonies. Most of these countries also employ single-member districts, which must be redrawn periodically to remain relatively equal in population.

Proponents of plurality electoral systems cite three main advantages: simplicity, stability, and constituency representation. The plurality system is easy to understand--voters simply place a mark next to their preferred candidate. The result of an election under the plurality system is also easy to understand--the candidate receiving the highest number of votes wins. This allocation rule is referred to as "first past the post."

Because of their tendency to produce a disproportionately large number of seats for the majority party, plurality systems usually produce strong single-party governments. This, in turn, produces a stable political system because there is no need to form coalition governments.

Plurality Systems and Single-Member Districts

Plurality electoral systems are most commonly associated with single-member districts and "first past the post" allocation rules. The use of single-member districts creates a strong link between representatives and their constituencies. Because each representative is beholden to a specific geographically defined constituency, legislative accountability and constituency services are both facilitated. Click here for more information on plurality first past the post systems.

Plurality Systems and Multimember Districts

A few plurality systems use multimember districts and different rules for allocating seats in the legislature. The allocation rules for multimember districts under plurality systems include the following:

Block Vote This voting system gives each elector as many votes as there are seats to be filled. The winners of an election are the candidates receiving the highest numbers of votes. Because the block vote allows the party with the majority of the votes to win all of the seats in a district, the use of the block vote system frequently results in an even greater distortion of seats to votes than does "first past the post" voting in single-member districts. Click here for more information on the block vote.

Limited Vote Under this voting scheme, each elector is given fewer votes than the number of seats to be filled. The expectation under the limited vote is that the majority party will not be able to carry all of the seats in an electoral district if the minority party presents a limited number of candidates and minority party supporters concentrate their votes on those candidates. This voting scheme is used in Spain to elect the upper house of the national parliament. Click here for more information on the limited vote.

Single Non-Transferable Vote This voting system is a variant of the limited vote--each elector is given only one vote. The single non-transferable vote was used in Japan to elect the lower house of the national parliament until 1994. It is still used in Japan to elect 152 of the 252 members of the upper house. Click here for more information on the single non-transferable vote.

Conclusion

The process of electoral district delimitation in a plurality system is important because the configuration of districts can affect the partisan, and possibly even the racial, ethnic, religious or linguistic composition of the legislature. The effect may be intentional, as in a partisan "gerrymander," or it may be unintentional. Even district boundaries drawn by a neutral boundary commission may unintentionally favour one party over others.

Majority Electoral Systems

Proponents of majority electoral systems claim that these systems have all of the advantages of a plurality system, i.e., simplicity, stability, and constituency representation. A majority system is relatively easy for the voter to understand. It tends to produce strong and stable governments, and each territorial constituency is represented by a single legislator. An additional benefit of a majority system is that each representative has the support of a majority of his or her constituents.

Under a plurality system, a candidate may be elected with less than a majority of the vote. In fact, the percentage of the vote necessary to win can be quite low, depending on the number of candidates competing for office and the spread of votes among candidates on the ballot. To prevent a candidate from winning a seat with less than 50 percent of the vote, allocation rules under a majority electoral system stipulate that the winning candidate must receive an "absolute majority" of the vote, i.e., 50 percent of the vote plus one more vote. Simply requiring a majority of the vote, with no further stipulations, creates the possibility of an election with more than two candidates producing no winner at all. Countries with majority electoral systems have adopted one of two solutions for this problem--a second round election or the alternative vote.

Two Round System

The central feature of the two round system is a requirement for a second election if the first election does not produce a candidate with an absolute majority of the vote. Under a two round system, voting occurs on two separate days, often a week or so apart. The first election is conducted in the same manner as a plurality "first past the post" election. However, if this election does not produce a candidate with more than 50 percent of the vote, a second election is held. The rules on who can participate in the second contest vary depending on the country and whether the election is a legislative or presidential election.

Under a "majority runoff" system, for example, if no candidate receives a majority on the first ballot, a second election is held. The only candidates in the second election are the two candidates who received the highest number of votes in the first election. This system is often used in presidential elections. It is also used in the United States for congressional elections in some southern states.

Under a "majority plurality" system, on the other hand, there is no drastic reduction in the number of candidates on the second ballot. The winner of second ballot in a majority plurality system is the candidate who receives the most votes, whether or not a majority of the votes is obtained. Some threshold may be imposed for candidates to stand at the second ballot.

The two, or second, round system is most commonly associated with France, where the majority plurality system is used for the election of representatives to the National Assembly. Electoral rules for the National Assembly stipulate that only candidates receiving the support of at least 12.5 percent of the registered electorate are entitled to compete in the second ballot the following week. The candidate who receives the highest number of votes in this second election is declared the winner. For more information on the two round system, click here.

Alternative Vote

The alternative vote is more accurately referred to as a "majority preferential" system. Under this system, voters not only indicate their first preference among the candidates, but also rank in order alternative preferences. To win, a candidate must receive a majority of the vote. To determine the winner, the number of first preference votes is tallied. If a candidate wins a majority of first preference votes, he or she is declared the winner. If no candidate receives a majority of first preference votes, the candidate with the fewest first preference votes is eliminated. The second preferences of voters who made this candidate their first choice are then distributed among the other candidates. If this redistribution does not produce a majority for one of the remaining candidates, the process of elimination and transfers continues until a majority is produced for one of the candidates. The alternative vote is used in Australia for elections to the House of Representatives. For more information on the alternative vote, click here.

Conclusion

Majority electoral systems can, and do, produce election outcomes that are just as disproportional as plurality electoral systems with regard to the ratio of seats to votes. This is not surprising, given that both systems rely almost exclusively on single-member districts. The district delimitation process in a majority system is, therefore, just as important as it is in a plurality electoral system.

Mixed Electoral Systems

Under a mixed electoral system, different formulas are used simultaneously to allocate seats from a single election. One feature all mixed electoral systems have in common is that an elector casts two votes, one for a candidate to serve as an electoral district representative and one for a party list of candidates. Among countries with mixed electoral systems, there are variations in the proportion of seats elected by district and the proportion elected by party list. There are also variations in the voting scheme (i.e., majority or plurality) adopted for district elections. And most importantly, there are variations in the relationship between district seats and party list seats.

In some countries, the total allocation of seats is based on the number of party list seats minus the number of district seats. In other countries, the allocation of seats is based on the number of party list seats plus the number of district seats. This distinction is crucial for the proportionality of seats to votes.

Mixed Member Proportional Systems

In countries such as Germany and New Zealand, the final seat tally for each party is calculated by subtracting the number of district seats that each party wins from the total number of party list seats to which it is entitled. The party list seats, therefore, are used to correct any disproportionality produced in the single-member plurality or majority seats. This is sometimes called the "mixed member proportional" system because the results are proportional, provided that a party exceeds any threshold vote percentage that may have been established. For more information on mixed member proportional systems, click here.

Parallel Systems

Countries such as Russia do not subtract district seats from party list seats, but rather add the two sets of seats together. Because the district seats and party list seats are independent of the one another, the party list seats do not correct for any seats-to-votes distortions created by the single-member district seats. The results in these mixed systems, sometimes referred to as "parallel" electoral systems, have tended to be disproportional. For more information about parallel electoral systems, click here.

Conclusion

One advantage of a mixed electoral system is that it uses single-member districts and, therefore, retains a strong link between representatives and their constituencies. At the same time, however, a high level of proportionality may be achieved, although the degree of proportionality is dependent on whether or not party list seats are used to correct for distortions produced by the electoral district seats.

The significance attached to the delimitation of electoral districts in a mixed system depends on whether or not party seats are used to rectify any distortions in the seats-to-votes ratio. If party seats are used to correct imbalances, then the process of delimiting districts is not much of an issue. If, however, party seats are not used as a corrective measure and disproportionate results are possible, the delimitation process becomes more important. In fact, the delimitation process may be as important as in a plurality or majority electoral system.

Proportional Systems

Most countries with proportional representation systems do not delimit electoral districts. However, two countries that use the single transferable vote, namely Ireland and Malta, do periodically delimit electoral districts [1].

Districts are redrawn in Ireland and Malta because the single transferable vote operates best with uniformly small multimember constituencies. Votes are cast by ranking candidates in order of preference, and if there are a large number of seats to fill, the number of candidates on the ballot may be overwhelming so the number of seats assigned to each constituency is usually relatively small. Malta employs only five-member electoral districts. In Ireland, electoral districts range in magnitude from three to five members.

Under a proportional system using the single transferable vote, electors rank candidates in order of preference. If a candidate has so many votes that an elector's first preference is not needed, or if the candidate has so few votes that there is no chance he or she can win office, the elector's first preference is transferred to a second or subsequent choice. To be elected, a candidate must obtain a quota of the votes. The quota is computed by dividing the total number of votes cast by one more than the number of seats to be filled, plus one additional vote. Only the prescribed number of candidates to be elected can reach the quota. For more information about the single transferable vote, click here.

The single transferable vote system differs from majority and plurality electoral systems in that election outcomes are more proportional. The single transferable vote shares two features in common with majority and plurality systems: voters choose among candidates, rather than between political parties; and the country is divided into relatively small territorial constituencies. These electoral constituencies, or districts, must be redrawn on occasion to accommodate shifts in the population. For example, in Ireland the constitution stipulates that constituencies be revised at least once every twelve years. Prior to 1980 and the establishment of an independent electoral commission, boundary changes and the allocations of seats in the legislature in Ireland were thought likely to benefit the political party in power.

Notes:

[1] The single-transferable vote is also used in Australia to elect members to its upper house, but each state is considered a district for election purposes, and therefore districts are not redrawn.