Voting systems in Northern Ireland
Voting systems are the method by which we elect representatives. A voting system determines the rules on how parties and candidates are elected.
First-past-the-post is used to elect MPs to the House of Commons.
Under first-past-the-post, the UK is divided into numerous voting areas known as constituencies. At a UK Parliamentary election (also known as a general election), voters put a cross (X) next to their preferred candidate on the ballot paper.
Ballot papers are then counted and the candidate who has received the most votes is elected to represent the constituency.
Single Transferable Vote (STV)
The Single Transferable Vote system is used to elect members of the Northern Ireland Assembly, European Parliament and Local Councils.
Multi-member constituencies are required for STV which means constituencies elect several representatives rather than just one.
Under STV, voters rank candidates in order of preference by marking 1, 2, 3 and so on next to the names of candidates on a ballot paper. A voter can rank as many or as few candidates as they like or just vote for one candidate.
Each candidate needs a minimum number of votes to be elected. This number is calculated according to the number of seats and votes cast and is called a quota. The first preference votes for each candidate are added up and any candidate who has achieved this quota is elected.
If a candidate has more votes than are needed to fill the quota, that candidate’s surplus votes are transferred to the remaining candidates. Votes that would have gone to the winner instead go to the second preference listed on those ballot papers.
If candidates do not meet the quota, the candidate with the fewest first preference votes is eliminated and the second preference votes are transferred to other candidates. These processes are repeated until all the seats are filled.