Proportional representation (PR) is achieved by any electoral system under which subgroups of an electorate are reflected proportionately in the elected body. The concept applies mainly to political divisions (political parties) among voters.
The term is also used for any of the various electoral systems that produce proportional representation. The aim of such systems is that all votes cast contribute to the result so that each representative in an assembly is mandated by a roughly equal number of voters, and therefore all votes have equal weight. Under other election systems, a slight majority in a district – or even simply a plurality – is all that is needed to elect a member or group of members.