The question of whether policy can be informed by evidence and at the same time be democratically legitimate is contentious. The present article draws on the philosophy of democracy and role-based moral theory in order to inform a reconciliation of rigorous use of evidence with democratic legitimacy. The article argues that in order to realise the value of equality that underpins their offices, democratic officials have a special moral responsibility to utilise appropriate, high-quality evidence to identify the means by which to realise citizens’ democratically chosen aims, because utilising appropriate, high-quality evidence that addresses how to achieve citizens’ aims makes it more likely that their aims will be realised. Furthermore, the paper argues that when value judgments must be made in the employment of evidence for policy, these value judgments should ideally be made by elected representatives serving on scientific advisory committees.