Party List PR
Party list systems are a family of voting systems in which parties put forward a list of candidates to stand for election. Seats are then allocated to candidates on the list in proportion to the share of the vote the party receives. The precise way in which the share of seats is calculated depends on the formulae used - of which the D’Hondt method is perhaps the most famous - but they all ensure that seats broadly match how the people voted.
At its simplest, each party provides a single list of candidates for the whole country and the ones who are elected represent the entire country without responsibility for any specific geographical area. In other variations, the country is divided into constituencies containing several seats and each party presents a list for each constituency. Constituency seats are allocated according to the share of the vote each party receives within that constituency. This feature allows voters to elect representatives for their particular area, who they can hold to account.
Party lists can also be either “closed” or “open”. In closed list systems - such as the one used in the UK to elect Members of the European Parliament - the party ranks their candidates with those they most want elected at the top. Voters vote for the party, rather than for individuals, and seats won are allocated to candidates in the order they are listed. By contrast, in open list systems the voters - rather than the parties - choose the order in which candidates on the list are awarded seats. There are various ways of doing this, and variations are used to great success in countries like Denmark, Finland, Iceland, Norway, Sweden and Switzerland.
More on Voting Systems.