5 Elections and Electoral Systems
Learn how electoral rules convert votes into offices and seats, how major electoral-system families differ, and how their design influences competition, representation, and government.
How electoral systems are designed
Elections translate citizens’ choices into public offices and, in many systems, legislative seats. determine who may vote and stand for office, how ballots are cast and counted, and how votes become seats. They shape political competition and representation, but do not determine outcomes alone: party organization, social divisions, campaign resources, political institutions, and whether elections are genuinely free and fair also matter.
Several design choices work together:
: the number of representatives elected from a district. Single-member districts elect one representative, while multi-member districts elect several.
Ballot structure: voters may select one candidate, rank candidates, or vote for a party list. Closed lists use a party-set candidate order; open lists let voters influence which listed candidates win.
Seat-allocation formula: the rule used to decide which candidate or party receives each seat.
Thresholds: minimum vote shares or other requirements a party must meet to qualify for seats.
These choices combine in different ways, so broad system labels can conceal important differences.
Plurality and majority systems
In , often called first-past-the-post, the candidate with more votes than any rival wins the seat, even without a majority. For example, when candidates receive , , and , the candidate with wins. The system is straightforward and gives each district a directly elected representative, but votes for losing candidates do not help elect anyone in that district. A party’s share of seats can therefore differ substantially from its share of votes.
Other systems seek broader support for each winner. In a , a second vote is held if no candidate meets the required in the first round. In ranked-choice majority systems, voters rank candidates and ballots are transferred according to preferences until a winner meets the rule for victory. These methods can reduce vote-splitting among similar candidates, but their ballot, counting, and campaign incentives differ; the precise method matters.
Proportional representation
aims to allocate seats in relation to parties’ vote shares, usually in multi-member districts. In party-list PR, voters select a party list, and seats are distributed among lists using an allocation formula. Larger districts generally make it easier for smaller parties to win seats, while thresholds and allocation formulas can limit that effect.
Some PR systems use open lists, which give voters a role in choosing which candidates from a party are elected. In , voters rank individual candidates in multi-member districts, and votes are transferred under the system’s counting rules to fill seats.
PR can make legislatures more closely reflect diverse political preferences. It may also produce several parties and require coalition-building.
Mixed electoral systems
Mixed systems combine district representatives with proportional or other seats. In , list seats are used to bring parties’ overall seat totals closer to their shares of the vote, subject to the system’s rules. In a , district and list seats are allocated separately, so the list tier does not compensate for disproportionality in district results.
Both arrangements provide more than one route to representation, but their overall proportionality differs.
Competition and party systems
influence how voters, candidates, and parties compete. In winner-take-all districts, voters may support a leading candidate strategically rather than their first choice if they fear their preferred candidate cannot win. Parties may concentrate on competitive districts, and political groups may form alliances before an election. These incentives can encourage larger parties, but do not guarantee a two-party system; regional support, social divisions, and political history also matter.
PR systems often make it easier for smaller parties to gain seats, which can encourage more parties to compete and sometimes make coalition governments more likely. The effect depends on , thresholds, party alliances, and other institutions. A high or small district can exclude smaller parties even under a system labeled proportional.
Representation, government, and policy
Representation has several dimensions. Geographic representation connects elected members to places, party representation reflects political preferences, and concerns whether legislatures include people from different social groups. Candidate-selection rules, party practices, district boundaries, and legal measures such as reserved seats or quotas can affect who is elected alongside the electoral formula itself.
Electoral systems also shape public policy indirectly by affecting which parties win seats, how governments are formed, and which groups can influence legislative bargaining. A single-party government may be able to act decisively when it has legislative support, while coalition governments may need to negotiate among partners. Neither outcome alone guarantees effective or representative policy: governing powers, courts, federal structures, party discipline, and public accountability also matter.
Electoral design involves trade-offs among proportionality, local ties, voter choice, simplicity, and incentives for cooperation. No single formula is universally best; effects depend on the wider political and institutional context.