Our forecast is virtually unchanged this week (we’re still using the same inputted poll shares as last week). It has moved a tiny touch towards Labour, as the Tories have seven days fewer to make the gains they need, but the change is almost imperceptible.
We still have the Conservatives as very slight favourites to be the largest party in the next Parliament, with a 54% chance to Labour’s 46%. We also make a Hung Parliament very slightly more-likely-than-not, with a 51% chance that no party secures a majority.
Our central forecast remains very close, too. In that scenario, the Tories are 25 seats short of a majority with just eight seats more than Labour: 301 to 293 (with the Lib Dems on 28).
Both the current polling and our forecast seem to have settled into a fairly steady state during the summer. For the past two months, the UK Polling Report Average has had the Tories on between 31 and 33%, Labour on 35 or 36% and the Lib Dems on 8 or 9%. For the same period, our central forecast has consistently had the Tories securing between 3 and 4.5% of the vote more than Labour and the two parties ending up within 20 seats of each other.
Date of forecast: 22 August 2014
Days till the election: 258
Inputted current average poll shares (from UK Polling Report)
Others (inc. UKIP): 22%
– UKIP: 12%
Forecast Election Day Shares (with 95% Prediction Intervals)
Con: 35.9% (±7.3, i.e. 29% – 43%)
Lab: 32.2% (±5.5, i.e. 27% – 38%)
LD: 12.5% (±8, i.e. 4% – 20%)
Implied point estimate shares for:
– Others (inc. UKIP): 19.4%
– UKIP: 10.6%
Forecast Election Day Seats (with approximate 95% Prediction Intervals)
Con: 301 (222 – 391)
Lab: 293 (207 – 367)
LD: 28 (23 – 35)
(Prediction intervals assume LD & others shares at central forecast, Con & Lab shares vary as per prediction intervals)
Central forecast: Con largest party, but short of a majority by 25
Approximate probabilities of key outcomes
Con largest: 54%
… with a majority: 27%
Lab largest: 46%
… with a majority: 22%
Hung Parliament: 51%
… with Con largest: 26%
… with Lab largest: 25%
(probabilities may not sum due to rounding)