Open list describes any variant of party-list proportional representation where voters have at least some influence on the (by the political party itself supplied) order in which party candidates are elected. This as opposed to closed list, which gives the voter no influence at all.
There are still differences possible between open list systems, each giving the voter varying amounts of influence:
- A very 'closed' open list would be one where a candidate has to get a full quota (usually Hare quota, but Droop quota is also possible) on his or her own in order to be elected. The total amount of seats won by the party minus the amount of those candidates that succeeded in getting this quota would then successively be given to that unelected candidate that was ranked highest on the list.
- For a 'more' open list the quota could be lowered to less than a full one instead (the Netherlands for example uses 25% for its Lower House elections). It is then (theoretically) possible that more candidates are eligible for a seat than the party deserves as a whole. It should therefore be clear in advance whether list ranking or absolute votes takes precedence in that case.
- The 'most' open list is the one where the absolute amount of votes every candidate got fully determines the "order of election" (the list ranking only possibly serving as a 'tiebreaker'). When such a system is used, one could make the case that 'within' every party an additional virtual single non-transferable vote election is taking place. This system is used in all Finnish multiple-seat elections, with ties being resolved by a toss.
Additionally, an open list system could also allow a voter to vote for the party as a whole in case he or she has no preference. In practice however, voting for the first candidate on the list will give the same effect.
The difference between "Open" and "Closed" lists has been debated in B.C., Canada, during the Learning Phase of Week 5, 2004. Learning Materials