A couple of correspondents have asked me to comment a bit further on the electoral reform proposals for Northern Ireland, and particularly what the consequences will be for the Northern Ireland Assembly. (Much less thought seems to have been given to this in Norn Iron than in Scotland or Waleshere.) 

There are basically two choices. The ratio of six seats per constituency was set in the Good Friday Agreement; but if you go down to 15 constituencies rather than 18, that means going down to 90 members of the Assembly rather than 108. If, however, the parties agree that they prefer to keep the Assembly at about its present size, one option that could be considered is to elect seven members for each constituency, giving a total of 105. (If the proposed 5% limit on variation in constituency sizes is adhered to, it would be very difficult to justify giving 8 members to three of them and 7 each to the other 12 just to keep the total number at 108).

More members per constituency would naturally be opposed by larger parties and supported by smaller parties. If you are trying to juggle three or four – or sometimes fewer – potentially winning candidates in an STV election, the more seats there are at play, the greater chance of something going wrong. In 2007 in West Tyrone, the SDLP ran three candidates, who between them polled enough votes to have won the party one seat, but were unable to transfer enough support internally to win.

On the other hand, more seats per constituency mean a greater chance of breakthrough for smaller parties. It is often said that to get elected you need a full quota of votes – 14.3% in a six-seat constituency, 12.5% in a seven-seater. This isn’t true; in a transferable voting system you can usually expect to pick up enough transfers to win if you get, say, 60% of a quota on first preferences. In the last Assembly election, the following candidates won even though their parties had less than a quota of first preference votes:

• Fermanagh-South Tyrone SDLP 14.0%
• North Belfast: SDLP 13.7%
• South Belfast: SF 13.2%
• East L’derry: SDLP 13.1%
• South Antrim: Alliance 13.1%
• Newry+Armagh: UUP 13.1%
• Newry+Armagh: DUP 12.9%
• Upper Bann: SDLP 12.7%
• South Belfast: Alliance 12.6%
• West Belfast: SDLP 12.2%
• North Antrim: SDLP 12.2%
• Lagan Valley: SF 12.2%
• Strangford: Alliance 11.5%
• South Antrim: SDLP 11.1%
• Mid Ulster: UUP 10.8%
• North Down: Alliance 10.2%
• East Belfast: PUP 9.8%
• South Down: UUP 9.6%
• North Down: Green 9.2%
• West Tyrone: Kieran Deeny 9,1%
• Lagan Valley: Alliance 9.0%
• North Belfast: UUP 8.4%

The above list includes seven SDLP MLAs, five Alliance, four UUP, three SF, one DUP and three others.

(On a slight tangent, let us just note briefly the historical fact that in recent memory, the UUP held Newry and Armagh, South Down and North Belfast, and the SDLP held West Belfast, not merely at Assembly level but at Westminster. Also NB the UKUP’s dismal 5.9% in North Down which they had held as a Westminster seat until 2001.)

Incidentally, the highest votes (more than 8.4%) received by parties which failed to gain a seat in 2007 were:

• West Tyrone, where the SDLP managed 14.5% and still screwed up the transfers between their candidates
• West Tyrone again, where the UUP got 8.9% but the DUP successfully balanced two candidates ahead of them
• Strangford, where the SDLP got 8.5% but there just weren’t quite enough transfers to get them in (boundary changes will help them next time)

So no single candidate (thus excluding the SDLP’s difficulties in Omagh and Strabane) who got more than 9% (0.63 of a quota) failed to get elected, and 22 out of 24 candidates who got more than 8.4% (0.59 of a quota) were elected.

The point of all this is that if you have seven seats rather than six, the vote share needed by a small party to win a seat in any given area drops. Of course, if you are a large party who fears that your vote may fall, you may also prefer the lottery of more members per constituency!