T he influential valence model of voting developed over the last decade by the British Election Study (BES) team assumes that party and leadership performance evaluations have a causal impact on party choice. An alternative perspective argues that such performance evaluations are instead the consequences of party choice. This article examines the analytical and empirical underpinnings of the BES valence model and compares it to the partydriven approach. To do so, it estimates cross-lagged structural equation models of the association between Labour Party preference and evaluations of the Labour government's performance during the 2005-10 British electoral cycle. It shows that party preference has a stronger effect on performance evaluations than vice versa; performance evaluations have no significant effect on party preference toward the end of the electoral cycle. The study also finds that, contrary to claims made concerning their merits as simplifying heuristics, performance assessments have no impact on short-term movements in party choice for less politically attentive voters. To a substantial degree, evaluations of party performance express-rather than explain-party choice, and would appear to have limited merit as simplifying heuristics.S tokes (1963, 1994) famously argued that competition between parties involves assessing policy performance and party competence in the delivery of agreed-upon goals. There is assumed to be a general consensus on the desirability of goals such as economic growth, the effective delivery of public services and the reduction of crime. Vote choice is based on which party or candidate is perceived to be the most competent to deliver these sorts of outcomes. This theory contrasts markedly with approaches to voting that emphasize differences in issues and/or ideological positions between parties and voters. In recent years, perceptions of party competence have become important explanations of political choices and electoral outcomes. Voters evaluate parties and politicians in terms of their competence and performance, and vote for those they think have delivered, or will deliver, valued outcomes.1 The significance of evaluating performance and competence for vote choice is now so embedded in our understanding of voting behavior that voter assessments of party competence on key issues are routinely included in election surveys. The American, British, Canadian, European and Irish election studies all now include questions on party issue competence (Wagner and Zeglovits forthcoming).A particular model of valence voting advocated by the current British Election Study (BES) team has recently become highly influential. Clarke et al. (2004Clarke et al. ( , 2009Clarke et al. ( , 2011 have instantiated an operationalization of valence voting that has reshaped understanding of British voting behavior in particular, but has also been assumed to have more general