How much does issue salience matter? A model with applications to the UK elections

Extensive research applies counterfactual simulation methodology to study parties’ optimal policy positions in multiparty elections. In recent years, this methodology has been extended to the study of variation in issue salience. We employ this method to estimate the electoral effects of changes in the salience of specific positional issue dimensions on parties’ success. Applied to British Election Study survey data from 2017 and 2019, we find that plausible issue salience changes could have shifted the parties’ projected vote shares by several percentage points. Our approach implies that the governing Conservative Party had electoral incentives to downplay positional issues, to magnify the relative effects of its non-policy advantage due to perceived competence and performance, among other factors. Labour would also have benefitted from reduced salience of Left-Right ideology. By contrast, the Liberal Democrats had strong electoral incentives to emphasize their moderate Left-Right position.