Editing Proportional representation (section)

=== How party-list PR works ===
{{Main|Party-list proportional representation}}

Party-list PR is the most commonly used version of proportional representation. Voters cast votes for parties and each party is allocated seats based on its party share.

Some party-list PR systems use overall country-wide vote counts; others count vote shares in separate parts of the country and allocate seats in each part according to that specific vote count. Some use both.

List PR involves parties in the election process. Voters do not primarily vote for candidates (persons), but for ''[[electoral list]]s'' (or ''party lists''), which are lists of candidates that parties put forward. The mechanism that allocates seats to the parties/lists is how these systems achieve proportionality. Once this is done, the candidates who take the seats are based on the order in which they appear on the list. This is the basic, [[closed list]] version of list PR.

An example election where the assembly has 200 seats to be filled is presented below. Every voter casts their vote for the list created by their favourite party and the results of the election are as follows (popular vote). Under party-list PR, every party gets a number of seats proportional to their share of the popular vote.

{| class="wikitable"
! colspan="2" rowspan="2" |Party
! rowspan="2" |Popular vote
! colspan="3" |Party-list PR{{snd}}Sainte-Laguë method
|-
!Number of seats
!Seats %
| rowspan="6" |[[File:Party list pr-example total seats.svg|frameless|upright=0.75]]
|-
| style="background:#D10000" |
|Party A
|43.91%
|88
|44%
|-
| style="background:#0008A5" |
|Party B
|39.94%
|80
|40%
|-
| style="background:#03AA00" |
|Party C
|9.98%
|20
|10%
|-
| style="background:#820084" |
|Party D
|6.03%
|12
|6%
|-
| colspan="2" |''TOTAL''
|''99.86%''
|''200''
|''100%''
|}
This is done by a proportional formula or method; for example, the [[Sainte-Laguë method]]{{snd}}these are the same methods that may be used to allocate seats for geographic proportional representation (for example, how many seats each states gets in the US House of Representatives). Votes and seats often cannot be mathematically perfectly allocated, so some amount of rounding has to be done. The various methods deal with this in different ways, although the difference is reduced if there are many seats{{snd}}for example, if the whole country is one district. Party-list PR is also more complicated in reality than in the example, as countries often use more than one district, multiple tiers (e.g. local, regional and national), [[open list]]s or an [[electoral threshold]]. This can mean that final seat allocations are frequently not proportional to the parties' vote share.