Prospective and comparative or retrospective and individual? Party leaders and party support in Great Britain

We argue that voters' assessments of party leaders are comparative and prospective rather than individual and retrospective. Therefore, a prospective leadership-comparison evaluation should outperform a leader-approval, retrospective indicator as a determinant of government and party popularity. Using data from 1984-92, a popularity function that includes a variety of economic and political components, and several dependent variables, we test this hypothesis by comparing the performance of a 'best prime minister' question and the more usual 'approval' questions about party leaders. We find that the former gives consistently better results than the latter.