Editing Proportional representation (section)

=== How the single transferable vote (STV) works ===
{{Main|Single transferable vote}}

The single transferable vote is an older method than party-list PR, and it does not need to formally involve parties in the election process. Instead of parties putting forward ordered lists of candidates from which winners are drawn in some order, candidates run by name, each voter casts one vote by marking preferences for candidates, with only one marked preference used to place the vote. Votes cast for the candidates determine the winners. 

STV uses [[Ranked voting|preferential ballots]]. The ranking is used to instruct election officials how the vote should be transferred in case the first preference is marked for an unelectable candidate or for an elected candidate who has an excess of votes needed to guarantee election. Each voter casts one vote, and the district used elects multiple members (more than one, usually 3 to 7). Because parties play no role in the vote count, STV may be used for nonpartisan elections, as with the city council of [[Cambridge, Massachusetts]].{{Citation needed|date=May 2025}} A large proportion of the votes cast are used to actually elect someone, so the result is mixed and balanced, with no one voting block taking much more than its due share of the seats. Where party labels are indicated, proportionality party-wise is noticeable.

[[Counting single transferable votes|Counting votes under STV]] is more complicated than under [[first-past-the-post voting]], but the following example shows how the vote count is performed and how proportionality is achieved in a district with 3 seats. In reality, districts usually elect more members than that in order to achieve more proportional results. A risk is that if the number of seats is larger than, for example, 10 seats, the ballot will be so large as to be inconvenient and voters may find it difficult to rank the many candidates, although 21 are elected through STV in some elections with no great difficulty.<ref>"Results: NSW Election 2019". ABC Elections. Archived from the original on 24 March 2019. Retrieved 23 March 2019</ref> In many STV systems, voters are not required to mark more choices than desired. Even if all voters marked only one preference, the resulting representation would be more balanced than under single-winner FPTP, due to each voter having just one vote and districts electing multiple members under STV.

Under STV, the ''quota'', an amount that guarantees election, is determined. In the example below, the [[Droop quota]] is used. In a three-seat district, any candidate who earns more than 25 percent of the vote is declared elected. Note that it is only possible for three candidates to each achieve that quota.

In the first count, the first preference (favourite candidate) marked on each of the ballots is counted. Candidates whose vote tally equals or exceeds the quota are declared elected as shown in the example below. 
[[File:Preferential_ballot.svg|thumb|Simplified example of an STV ballot]]The table below shows the initial count, or first round or stage, of the vote count process.

Quota is 25 percent plus 1 (Droop quota).

Jane Doe and Fred Rubble are elected in the first round.
{| class="wikitable"
!Candidate
! colspan="2" |Party
!Popular vote<br>(first preferences)
!Elected?
!If elected: surplus votes
|-
|Jane Doe
| style="background:#D10000" |
|Party A
|40%
|'''Yes'''
|15%
|-
|Fred Rubble
|
|Party B
|30%
|'''Yes'''
|5%
|-
|Joe Smith
| style="background:#D10000" |
|Party A
|16%
|
|
|-
|John Citizen
|
|Party A
|11%
|
|
|-
|Mary Hill
| style="background:#0008A5" |
|Party B
|3%
|
|
|-
| colspan="3" |''TOTAL''
|''100%''
|
|
|}
Next, surplus votes belonging to those already elected, votes the candidates received above the quota (votes that they did not need to be elected), are transferred to the next preference marked by the voters who voted for them. Continuing the example, suppose that all voters who marked first preference for Jane Doe marked John Citizen as their second choice. Based on this, Jane Doe's surplus votes are transferred to John Citizen. John Citizen achieves the quota and so is declared elected to the third and last seat that had to be filled. 

Even if all of Fred Rubble's surplus had gone to Joe Smith, the vote transfer plus Smith's original votes would not add up to quota. 

Party B did not have two quotas of votes so was not due two seats, while Party A{{Snd}}with 67 percent of the vote{{Snd}}was. It is possible, in realistic STV elections, for a candidate to win without quota if they are still in the running when the field of candidates has thinned to the number of remaining open seats.

In this example, the district result is balanced party-wise. No one party took all the seats, as frequently happens under FPTP or other non-proportional voting systems. The result is fair{{Snd}}the most popular party took two seats; the less popular party took just one.  

As well, the most popular candidates in each party won the party's seats. 81 percent of the voters saw their first choice elected. At least 15 percent of them (the Doe first, Citizen second voters) saw both their first and second choices elected{{Snd}}they were likely more than 15 percent if some "Citizen first" votes gave their second preference to Doe. Every voter had the satisfaction of seeing someone of the party they support elected in the district. 

==== Final-round vote tallies and party satisfaction break-down ====
Quota is 25 percent plus 1 
{| class="wikitable"
!Candidate
! colspan="2" |Party
!Current vote total
!Elected?
!Party
!First-preference votes<br>for candidates of party
!Number of<br>seats
!Party seats %<br>under STV
|-
|Jane Doe
| style="background:#D10000" |
|Party A
|Already elected (25%+1 vote)
|'''Yes'''
| rowspan="3" |Party A
| rowspan="3" |67%
| rowspan="3" |2
| rowspan="3" |67%
|-
|John Citizen
| style="background:#D10000" |
|Party A
|11% + 15% = 26%
|'''Yes''' 
|-
|Joe Smith
| style="background:#D10000" |
|Party A
|16%
|
|-
|Fred Rubble
| style="background:#0008A5" |
|Party B
|Already elected (30%)<br>(surplus votes not transferred)
|'''Yes'''
| rowspan="2" |Party B
| rowspan="2" |33%
| rowspan="2" |1
| rowspan="2" |33%
|-
|Mary Hill
| style="background:#0008A5" |
|Party B
|3%
|
|-
| colspan="3" |''TOTAL''
|''100%''
|''3''
|
|''100%''
|''3''
|''100%''
|}

Under STV, to make up the 200-seat legislature as large as in the examples that follow, about 67 three-seat districts would be used. Districts with more seats would provide more proportional results{{Snd}}one form of STV in Australia uses a district with 21 members being elected at once. With a larger district magnitude, it is more likely that more than two parties will have some of their candidates elected. 

With a lower district magnitude, it is more likely that only two parties will have their candidates elected. For example, in [[Malta]], where STV is used with 5-member districts, it is common for successful candidates to receive 16.6 percent of the vote in the district. This produces a high effective threshold in the districts, and the country maintains a very strong two-party system.<ref name="auto1">{{cite web | url=https://electoral.gov.mt/ElectionResults/General | title=Electoral Commission of Malta }}</ref> However, about 4000 voters in a district would be enough to elect a third-party candidate if voters desired, but this seldom happens.<ref name="auto1" />{{Original research inline|date=May 2025}}

Conversely, New South Wales, which uses STV to elect its state legislative council in 21-seat contests, sees election of representatives of seven or eight different parties each time.<ref>{{cite web | url=https://elections.nsw.gov.au/elections/past-results/state-election-results/2023-nsw-state-election-results#legislativecouncilresults | title=2023 NSW State election results }}</ref> In this election, about 1/22nd of the vote in the state is enough to take a seat, and seven or eight parties take at least that many votes, demonstrating a different voting pattern than Malta exhibits.