Social-psychological models of voting behaviour systematically downsize the relevance of party leader evaluations by conceiving them as mere consequences of causally prior partisan attachments. However, the validity of this interpretation depends heavily on the effectively exogenous status of party identification. Empirical research shows that the assumed exogeneity of partisanship is, at best, doubtful. In such a context, single-equation models of voting are likely to provide seriously biased estimates. By employing the proper econometric procedures (instrumental variable estimation) and the most appropriate data sources to address causality issues (panel data) this study provides strong support in favour of the personalisation hypothesis.