STV

• Single Transferable Vote (STV)


  Where is it used and how does it work?
• STV


  1. Used in elections for the Northern Ireland Assembly and Scottish councils

  2. Uses multi-member constituencies, in the case of the NI Assembly there are 18 each returning 6 members

  3. Voters number their choices preferentially

  4. 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

  5. Results are calculated using a complex counting process that takes into account voters' second preferences

  6. If a candidate reaches the quota on the first round of counting, they are elected and their second preferences are redistributed

  7. 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

  8. This process continues until all of the seats are filled
• Advantages of STV


  • Highly proportional system, with a very close correlation between votes and seats
  • Voter choice is very high, as voters can choose between candidates standing for the same party, as well as between candidates from different parties, and rank their candidates preferentially
  • In Northern Ireland, it has created power-sharing governments which allows representatives of the two rival communities to work together, helping to end 30 years of the Troubles
  • These governments also always have majority support
  • In Scottish Local Elections, after the 2022 elections 94% of councils had no overall control, compared to only 38% in 2003 when FPTP was used
• Disadvantages of STV


  • In large multi-member constituencies, the member-constituency link may be weak
  • Power sharing governments may bring rival groups together, but they're still prone to conflict, as shown by the suspension of the Northern Ireland executive for 40% of its existence
  • Counting votes is slow and the results are difficult to understand
  • Can lead to 'donkey voting' where the candidate whose surname is first alphabetically is elected
• The Northern Ireland Assembly (Stormont) was suspended for nearly 2 years following the 2022 Northern Ireland Assembly elections as the DUP refused to go into coalition with Sinn Fein in protest against the Northern Ireland Protocol
• This meant that there was no executive and business in Northern Ireland was run by Westminster until the government was restored again in February 2024
• This shows a key weakness of the Single Transferable Vote (STV) system creating coalition governments, though it must be recognised that the context in Northern Ireland and animosity between the parties is a unique context and that single party government is impossible without threatening violence
• Why is STV used where it is?

  • STV was chosen for Northern Ireland because it is a highly proportional system, likely to ensure the broadest possible representation of different parties
  • In view of the background of conflict between the two communities, it was important to avoid single-party domination, which could've derailed the fragile peace process
  • The use of STV ensures governments are power-sharing bodies drawn from both sides of the divide
  • The lack of single member constituencies is also less of a problem, as representatives represent religious communities more than they do geographical communities