In the last election, we saw 50 new list seats added to the electoral system. That begs an interesting question, what would happen if we didn’t add these seats? In order to answer this, I’ve built a basic spreadsheet to calculate list seats, and stopped at 100 rather than 150, using the old list allocations.

Now, there's something not quite right with my calculations, because I have the LDs coming out with 1 more seat in WMids than they did at 150, which doesn't make sense, because removing 50 seats shouldn't add to it. I'm assuming there's some kind of weighting towards smaller list vote shares to explain this, possibly D'Hondt.

Anyway, here is a table showing people's net change by moving back to 100 seats.

Now, we examine the ups and downs for a 100 seat Parliament.

Finally, and perhaps this is the most illuminating sheet, we look at percentage of seats for each party in both the old and new systems.

So, the winners from the new system are pretty dispersed. The Lib Dems and Independents have done well from the new system, as has Coalition and the Conservatives to a lesser extent, however Labour has really suffered from the new system, as they've simply failed to pick up enough lists to keep pace with everyone else. The WNP lose simply by virtue of Parliament growing around them, under the old system they'd win 3/5 Welsh seats, which is pretty bloody impressive.

There are some flaws in this model. I calculated the list vote using a weighting equal to (Vote/1 seats), but clearly that wasn't in use by the Quad, because I've got the LDs gaining one seat under the old system, which is impossible.

The real thing we've learned is that the idea that Solidarity was boosted by a generous list system is simply false.