Single Transferable Vote
Where is it used?
he Northern Ireland Assembly, European Parliament elections in Northern Ireland, Scottish council elections
How does it work?
· It uses multi-member constituencies; in the case of the Northern Ireland Assembly, there are 17, each returning 6 members.
· Voters number their choices preferentially: 1, 2, 3 etc.
· In order to be elected, a candidate needs to achieve a quota, arrived at using the Droop formula, which divides the number of votes cast by the number of seats contested plus one.
The results are calculated using a complex counting process that takes into account voters' second preferences. If a candidate reaches the quota on the first round of counting, they are elected and their second preferences are redistributed. If no one attains the quota, the least popular candidate is eliminated and the second preferences of those who voted for this candidate are transferred. This process is continued until all the seats are filled.
Scottish council elections
STV gives voters a large choice and allows them to show a preference between candidates of the same party.
Voters have a choice of six representatives when deciding whom they wish to pursue their grievances.
It helps small parties win seats.
The overall outcome is a multi-party system. In Northern Ireland, five different parties win a significant number of seats.
It favours a 'power-sharing system' where all parties have a place in the Assembly and in government. This is essential in a deeply divided society such as Northern Ireland
· There is a close correlation between votes and seats.
· Voter choice is high; it is possible to choose between candidates standing for the same party as well as between candidates from different parties.
· In Northern Ireland it has created a power-sharing government that enables representatives of the two rival communities, the unionists and nationalists, to work together, ending 30 years of violent disturbance in Northern Ireland.
· It is not fully proportional, particularly where smaller multi-member constituencies are used.
· In large multi-member constituencies, the link between the member and the voters may be weak.
· Power-sharing governments may bring rival groups together but they are still prone to conflict. The Northern Ireland executive was suspended several times in its early years, including for almost five years in 2002-07 as a result of a breakdown of trust. Co-operation between the parties broke down again early in 2017, triggering further elections. STV did not help the more centrist parties in the long term. The dominant parties are now the Democratic Unionist Party and republican Sinn Fein. Since 2007 they have replaced the more moderate Ulster Unionist Party and Social and Democratic Labour Party. Voting across community lines is still rare.