A leading psephologist, and member of the exit poll team, on how electoral geography—and the voting system—helped to give Boris Johnson a majority of 80by Stephen Fisher / December 13, 2019 / Leave a comment
Let’s start with the mechanics. The Tories won 57 seats that they did not win in 2017, but they lost 10, so they are up 47 net, from 318 to 365 seats.
A standard uniform change projection from the Great British shares of the vote (Con 44.7 per cent, Lab 33 per cent, Lib Dem 11.8 per cent, with the SNP on 45 per cent of the Scottish vote and Plaid Cymru on 9.9 per cent of the Welsh vote) would suggest the following seats outcome: Conservative 354, Labour 211, LD 17, SNP 46, Plaid three, Green one, and Others (from Northern Ireland) 18.
That would be a majority of 58, which would make for somewhat less dramatic headlines than the figure of 80, but is not profoundly different from the actual outcome: Conservative 365, Labour 203, LD 11, SNP 48, Plaid four, Green one, and then 18 Northern Irish MPs.
The fairly modest net differences in these totals, as well as individual differences in who won which particular seats, should be investigated and understood. But that is work for another day. The main point is that the actual seat totals achieved yesterday are broadly what you would expect given the total number of votes each party won, our electoral system and the geography of the vote in 2017. The shape of the new House of Commons, and especially the substantial Conservative majority, are not due to any peculiar pattern of different shifts in different seats. Rather, just as my recent Prospect article pointed out for both the 2015 and 2017 elections, uniform change projections have again proved to be a decent guide for the 2019 outcome.
If follows that the important questions for understanding how Boris Johnson secured his majority are why the Conservative vote was up 1.2 points, why the Labour vote was down 8 points, and why the Liberal Democrats were only up 4.2 points.
The answers as to what drove these shifts in vote shares will be much debated, but the movement should not have come as a surprise given they are broadly in line with the opinion polls for Great Britain, Scotland and Wales. Similarly, the seats outcome should have come as no surprise. That is not to say that I or anyone else knew in advance what the outcome would be. Rather,…