Forecasting the Vote for a Third Party: The British Liberals, 1974–2005

Abstract

While for multiparty systems the development of vote function forecast models for the incumbent party and the official opposition party is commonplace, only rarely do these models try to forecast the vote for a third party. Can third party vote shares be forecasted with reasonable accuracy? We explore this question within the context of British politics. Our model proposes that the British Liberal party vote is mostly driven by the extent to which the UK electorate approves or disapproves of the official opposition leader. Our results are consistent with the idea that once the decision has been made to punish the incumbent government, a voter must then decide whether to support the official opposition party or another smaller party.