Martin McGuinness has today added his support to the notion of cutting the Northern Ireland Assembly to 90 seats from the current 108, ie to five per constituency instead of six.

How would this have affected the 2011 election? It’s a fairly straightforward calculation to raise the quota in each seat from 14.29% to 16.67% and work out who would have won. Of course, one has to apply the caveat that if there had been only five seats rather than six up for grabs in each constituency, parties might have managed their nominating strategies differently. But bearing that in mind, it’s reasonably clear in the majority of cases that the party that won the sixth seat in 2011 would likely not have won if there had been only five seats up for grabs. This applies fairly clearly in the following cases:

	2011 outcome	2011 last elected	5-seat projection
Lagan Valley	4 DUP, 1 UUP, 1 Alliance	DUP	3 DUP, 1 UUP, 1 Alliance
Strangford	3 DUP, 2 UUP, 1 Alliance	UUP	3 DUP, 1 UUP, 1 Alliance
North Antrim	3 DUP, 1 SF, 1 TUV, 1 UUP	TUV	3 DUP, 1 SF, 1 UUP
East Antrim	3 DUP, 1 UUP, 1 Alliance, 1 SF	SF	3 DUP, 1 UUP, 1 Alliance
East Belfast	3 DUP, 2 Alliance, 1 UUP	UUP	3 DUP, 2 Alliance
South Antrim	3 DUP, 1 UUP, 1 SF, 1 Alliance	DUP	2 DUP, 1 UUP, 1 SF, 1 Alliance
East Londonderry	3 DUP, 1 SF, 1 SDLP, 1 Ind	DUP	2 DUP, 1 SF, 1 SDLP, 1 Ind
South Belfast	2 SDLP, 1 DUP, 1 Alliance, 1 UUP, 1 SF	SDLP	1 SDLP, 1 DUP, 1 Alliance, 1 UUP, 1 SF
Newry and Armagh	3 SF, 1 SDLP, 1 UUP, 1 DUP	SF	2 SF, 1 SDLP, 1 UUP, 1 DUP
Foyle	3 SDLP, 2 SF, 1 DUP	SDLP	2 SDLP, 2 SF, 1 DUP
West Belfast	5 SF, 1 SDLP	SF	4 SF, 1 SDLP

There are some cases where it gets a bit trickier – especially if the last elected and the runner-up came from the same party or from similar community backgrounds, it’s likely that their combined votes would actually have excluded someone else. I make that call in the following cases:

	2011 outcome	Un v Nat	2011 last elected	5-seat projection	loser	note
North Down	3 DUP, 1 Alliance, 1 UUP, 1 Green	Un 57%, Nat 4%, Oth 39%	Green	3 DUP, 1 Alliance, 1 UUP	Green	This is really difficult to call between DUP and Greens
Upper Bann	2 DUP, 2 UUP, 1 SF, 1 SDLP	Un 55%, Nat 39%, Oth 7%	SDLP	2 DUP, 1 SF, 1 UUP, 1 SDLP	UUP	Nat transfers enough for two seats.
North Belfast	3 DUP, 2 SF, 1 SDLP	Un 49%, Nat 44%, Oth 7%	DUP	3 DUP, 2 SF	SDLP	Unionist transfers certain to save third DUP; SDLP way behind SF.
Fermanagh and South Tyrone	3 SF, 2 DUP, 1 UUP	Un 46%, Nat 50%, Oth 4%	SF	3 SF, 1 DUP, 1 UUP	DUP	Nat transfers enough for three seats.
West Tyrone	3 SF, 1 DUP, 1 UUP, 1 SDLP	Un 33%, Nat 59%, Oth 8%	UUP	3 SF, 1 DUP, 1 UUP	SDLP	Unionists scrape last seat, SDLP far behind
Mid Ulster	3 SF, 1 DUP, 1 UUP, 1 SDLP	Un 32%, Nat 64%, Oth 4%	SF	2 SF, 1 DUP, 1 UUP, 1 SDLP	SF	This one’s really tight, but in the end I think the SDLP scrape that last seat.
South Down	2 SDLP, 2 SF, 1 DUP, 1 UUP	Un 29%, Nat 66%, Oth 5%	SDLP	2 SDLP, 2 SF, 1 DUP	UUP	Nat transfers enough for four seats.

In general, one expects a broad reform reducing the number of seats to hit the largest parties most in absolute terms, and the smallest parties most in relative terms. But this is not what I see happening here. The losers by my count are disproportionately from the medium-sized parties. Starting with the smallest groups, Jim Allister would not have won the TUV’s sole seat in North Antrim had there been only five seats there, and the Greens would probably not have retained their seat in North Down. But the late David McClarty would have still won in East Londonderry, and, perhaps rather surprisingly, all eight Alliance seats would have been safe enough – in a couple of cases, they would have benefited from Nationalist transfers which in the real election went to runners-up.

All of the big parties would lose four seats each – the DUP down from 38 to 34 (if the Greens are unlucky in North Down), SF down from 29 to 25, the UUP from 16 to 12 and the SDLP from 14 to 10. Unionist membership of the Assembly remains at 52%, the Nationalist proportion dips imperceptibly from 40% to 39%. This would not have affected the allocation of ministries in the Executive between parties. But it would certainly have affected the relative dominance of the largest two parties within their respective groups.

It has to be said that these numbers are very speculative, and also vulnerable to small variations. The UUP and SDLP both had a pretty lousy election in 2011, and a small uptick in their support could shift the notional results quite a bit. But the point remains that raising the quota from 14.3% to 16.7% particularly affects parties whose support is at around that level in a lot of constituencies.