Wednesday, June 07, 2017

Final UK Election Seat Forecasts

Opinion polls tend to just give us the percentage of the vote for each party and not how this translates into parliamentary seats. Last time David Cameron gained 6.5% more of the votes than Labour which translated into a slim working majority with 330 seats.

Four companies have models that predict the likely number of seats based on polling data. Their final projections as at this morning 7th June are below.

The projections range from a hung parliament using the YouGov model to a hundred seat majority using Nigel Marriott's model.

YouGov's model uses a new methodology with a much larger sample (50,000) with multilevel regression and post-stratification analysis against constituency census demographics and British Election Study data. Their new approach has been praised but the predictions have been heavily criticised. It will be interesting to see how their individual seat predictions perform.

Nigel Marriott has the largest Conservative majority and he predicts Labour's worst result since 1935. He has produced a useful set of slides explaining the background to his predictions.

He is predicting a Conservative lead of 9.5% and a combined Labour/Tory vote of 81%. In his model the Lib Dems are reduced to just two seats. He believes there some realignments taking place due to Brexit and thinks Labour will do better in more southern Remain seats (eg taking Brighton Kempton and retaining Hove) but worse in more Northern Leave seats. He doesn't believe the assumptions of higher young people turnout that some polling companies have used.

There is a danger I think that the polls have created a narrative of Labour narrowing the gap which fits with the poor Conservative campaign and the strong showing for Labour on social media. Almost all of the most shared and most viewed posts are pro-Labour. However, this may simply reflect the younger cohort that supports Labour and the well organised Momentum social media campaigns. many older voters will be less active on social media and there is a question mark over whether social media posts do anything other than confirm existing viewpoints.

We shall have a better picture at 10pm tomorrow when the first exit polls are reported.