Senedd Elections Maths and Politics

(Notes on how to stop Reform becoming the largest party.)

Defying all statistical and mathematical calculations thousands of well-intentioned Welsh folk from Left and Green politics are cheerfully planning to reduce the chances of denying Reform a critical role after the Senedd Elections on May 7^th, 2026.

And in a few day’s time  (April 9^th) it will be too late for a range of groups to think again.

It is frightening that many political activists still haven’t grasped how the Senedd elections are going to work.̂̂̂

So, with apologies and congratulations to those who are on top of it all, let’s have a summary of the problems.

The D’Hondt system with closed lists means that you only have ONE vote. And you vote for ONE party list, each of which may offer up to six candidates.

The D’hondt system is the least proportional of all the PR systems. It can arguably produce less proportionality than the present system. It was designed to enhance the outcome for larger parties (usually the first and second) and reduce the outcome for smaller parties and independents.

There is no lowest percentage that guarantees you a seat. (And 5% certainly won’t cut it).

The maths

I have taken an MRP poll and applied the result to a D’Hondt simulator. (Explainer: MRP polls have much larger samples than others and produce results down to a constituency level. The one that I have studied very closely has figures for every Welsh Senedd seat. A D’Hondt simulator does all the boring calculations that turn the votes for each list into the number of seats won.)

The Poll I used was recent, but it doesn’t make any difference in demonstrating that outcomes are not consistent or proportional.

FOR EXAMPLE:  The Conservatives poll 11% in Caerdydd Ffynon Taff, but they don’t get a seat. But they also poll 11% in both Brycheiniog Tawe Nedd and Casnewydd Islwyn and get a seat in each.

Labour poll 11.5% in Bangor Conwy Môn but do not get a seat.

The LibDems poll 10% in Gŵyr Abertawe, but they don’t get a seat.

The Greens poll 11.5% in both Caerdydd Ffynon Taff and Caerdydd Penarth and get a seat in each.

At the other end of the spectrum Plaid poll 47.5% in Bangor Conwy Môn and pick up 4 seats (66% of the six seats).

Reform poll 31% in Sir Fynwy Torfaen and get 3 seats. (50% of the six).

CONCLUSION: It is unlikely that any party with 10% will get a seat in any constituency. 13% probably will get you a seat. Regarding anything in between as a certainty could be very foolish.

We must challenge smaller parties and independents of the organisational, financial and other impediments to turning out a decent vote. In each of the 16 constituencies those who run and fail to win a seat will be guilty of simply depriving other parties of votes that could have given them an extra seat at Reform’s expense. And it may even be the case that a smaller party wins a seat but enables Reform to win two.

In Fflint Wrecsam. Labour was forecast with 21.5% but only get one seat. But that Labour vote might well create two extra seats for Reform and / or the Tories

OK, there is a counter argument that says it may all be the other way round. That there are voters who will never vote Labour or Plaid and have an alternative to voting Reform. But there is, so far, minimal evidence to take that scenario seriously.

Is it too much to ask reputable polling organisations to produce projections for each of the sixteen seats based on actual polling in each of them and showing the seat allocations that this would produce?

The Politics

(Please read the admirable posting by Sam Swash. ‘Wales is about to hold an election most voters won’t understand’)

It is profoundly anti-democratic to have an electoral system in which very few voters will understand why the outcomes are like they are.

A lot of people will have their prime objective as “stopping Reform”. This should certainly be the overwhelming concern for all of us. It must come before any residual loyalty to any party or candidate.

So – sixteen separate calculations must be made for each of the Senedd seats.

The Tories should be regarded as probable enablers of a Reform government. It is difficult to see any reason to vote for them.

Until a few weeks ago the sensible view seemed to be that the only parties that could stop Reform were Plaid and Labour. There might be circumstances in some constituencies where you had to hold your nose and have a bucket handy and vote Labour. But I am not sure that there is a single seat in Wales to which that now applies. We really, really need to see MRP type polls and D’hondt simulations for each seat separately.

But even where Labour is a small margin ahead of Plaid, we must consider some other factors. The current direction of travel is that Labour continue to lose ground and that Plaid and the Greens are steadily growing.

The Greens deserve to be taken seriously given their spectacular surge in England and in particular their massive victory in the Gorton and Denton By-Election. In some opinion polls they have nudged ahead of Labour and are running second to Reform. Furthermore, some sort of agreement between the Greens and Plaid seems an increasingly helpful idea.

But the Green Party is far better established in England than it is in Wales, and one of the main reasons for that is that many potential green voters and activists are deeply positioned in Plaid. And Plaid deserves gratitude from all of us for stopping Reform in Caerphilly.

Even now it would be a great help if Plaid and the Greens could come to some kind of tactical pact.