Single transferable vote

Single transferable vote

1. Used in the Northern Ireland Assembly, in Northern Ireland and Scotland for local government, and in Northern Ireland only for European Parliament.

2. Features

   • Electors vote preferentially by ranking candidates as there are seats to fill in each constituency.
     • There are multi-member constituencies.
       • The Northern Ireland Assembly has 18 constituencies, each returning 6 members. In local elections in Northern Ireland there is a mixture of 5-6 and 7 member constituencies.
       • Political parties are able to put up as many candidates as there are seats to fill in each constituency.
         • Candidates are elected if they achieve a quota of votes. This quota is calculated on the basis of the Droop formula
           • Votes are counted, first, according to first preferences. If any candidate achieves the quota, additional votes for him or her are counted according to second or subsequent preferences.
             • If this process still leaves some seats unfilled, the candidate with the fewest votes drops out and his or her votes are redistributed according to second or subsequent preferences.

3. Advantages

   • The system is capable of achieving highly proportional out comes.
     • Competition amongst candidates from the same party means that they can be judges on their individual records and personal strengths.
       • The availability of several members means that constituencies can choose who to take their grievances to.

4. Disadvantages

   • The degree of proportionality achieved in this system can very, largely on the basis of the party system.
     • Strong and stable single-party government is unlikely under STV.
       • Multimember constituencies may be divisive because they encourage competition amongst members of the same party.

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