As the dust settles on the results of the 2014 local and European elections several questions remain unanswered about what the results mean for the future of British politics: Who will win the next general election? How well will UKIP do? Are the Liberal Democrats doomed?
Although local and European elections are notionally concerned with who represents us at the local and European level, most media analysis and political commentary about the electoral results is more concerned with national politics (as indeed are the decisions of many voters). Two years ago I developed a simple statistical model that tries to predict the outcome of general elections from local election results. Although local election and general election results tend to be quite similar to begin with (the two are 90% correlated) a statistical prediction might offer a better indicator of what is likely to happen in the future then simply taking the results at face value. Local election results tend to differ from general elections in certain predicable ways – for example incumbent government parties have tended to perform worse on average at local elections than their eventual general election results by about 4.5%. Controlling for these factors improves the predictive power of local elections by about 40%: the vote share for each party at local elections is 4.4 percentage points different on average from their share at the next general election. The average difference between the vote shares fitted by the model and the eventual results is only 2.7.