ELECTION FORECASTS NOWCAST, IF THE #GE2015 WAS HELD TODAY

The votes and seats totals shown elsewhere on this site are forecasts.  They are predictions about what will happen on 7 May 2015.  These forecasts are based on where we think the polls are today, combined with historical evidence about how support for parties evolves as elections approach.  As such, they will have significant uncertainty until just before the election.  Because they are predictions about what will happen on 7 May, there is no way to evaluate them until the election occurs.
This tab provides our estimates of what constituency polls conducted today in every constituency would find.  This is not exactly an estimate of what would happen in an election today, and it may not exactly match the current national polls.  Since Lord Ashcroft Polls is currently publishing the vast majority of constituency polls, these Nowcasts specifically aim to predict where those polls would find each constituency in the question “Thinking specifically about your own Parliamentary constituency at the next General Election and the candidates who are likely to stand for election to Westminster there, which party's candidate do you think you will vote for in your own constituency?” 
This Nowcast allows us to evaluate the performance of our model at interpolating the likely situation in unpolled constituencies every time Lord Ashcroft releases polls of previously unpolled constituencies.  While there are many other aspects of our forecasting model, one important component is to correctly determine what is likely to be happening right now in unpolled constituencies, or in constuencies that have not been polled in many months, and so the degree to which we are successful at that is important.  Every time there are new constituency polls released, we will write a blog post evaluating how well our Nowcasts predicted those constituency polls at the LSE General Election blog.
Here are our estimates of what these hypothetical constituency polls would look like in every GB seat:

Sortable table of current vote share for every party in every seat.

Sortable table of current probability of victory for every party in every seat.

If we aggregate the vote shares to the regional level, we get these totals:

	Con	Lab	LD	SNP	PC	GRN	UKIP	Oth
East Midlands	32	35	7	0	0	6	19	1
East of England	37	22	11	0	0	8	22	1
London	29	43	10	0	0	7	10	1
North East	20	49	7	0	0	6	18	1
North West	24	45	9	0	0	5	16	1
Scotland	12	31	7	43	0	4	2	1
South East	41	19	12	0	0	7	18	2
South West	36	19	17	0	0	9	18	1
Wales	19	40	8	0	12	4	16	1
West Midlands	31	35	7	0	0	6	20	2
Yorkshire and The Humber	23	41	8	0	0	6	20	1

If these seat predictions and vote predictions were aggregated up to the GB level, we get these totals:

Party	Lo	Seats	Hi	Swing	Lo	Votes	Hi	Swing
Conservatives	248	254	262	-52	29.4%	29.8%	30.2%	-7.1%
Labour	294	302	311	44	31.8%	32.3%	32.7%	2.6%
Liberal Democrats	19	22	25	-35	9.5%	9.8%	10.1%	-13.7%
SNP	35	41	46	35	3.5%	3.6%	3.8%	1.9%
Plaid Cymru	1	2	3	-1	0.5%	0.6%	0.6%	-0.0%
Greens	1	2	3	1	6.2%	6.5%	6.8%	5.6%
UKIP	5	8	10	8	15.8%	16.1%	16.5%	13.0%
Other	1	1	1	0	1.2%	1.3%	1.4%	-2.3%