As of this morning, updated polling both nationally and regionally has been included into the model to produce the final PME Politics forecast.
The 'polls plus' model projects a result of:
Lib Dems: 10
This is based on an estimated swing of around +9 for the Conservatives on their 2015 results. The Butler swing at the aggregate level would therefore be -1 (a swing towards Labour).
Accounting for forecasting errors, the model is projecting a Conservative majority of somewhere between 60 and 30 seats, with the central projection being about 45.
After the results come in, I will run a full disgnostic on the model and write a piece discussing its accuracy, what worked well and what didn't, and what the next PME Politics forecast might look like.