'What do we know? What should we do?' Melding research validity and rhetoric in the analysis of policy making

'Evidence-based policy and practice' was proposed to usher in an era where explicit use was made of evidence ('what we know') to inform decisions made about policy and practice ('what we should do'). Critics have focused on its allegedly technocratic nature, motivating some to develop analyses of policy making that take account of inherent social processes. One example is rhetorical analysis, which focuses on the use of discourse and argumentation in the policy-making process (Russell et al, 2008). In this paper, I welcome the insights that can be attained using rhetorical analysis, but argue that too dramatic a swing towards an interpretivist approach risks jettisoning valuable work on research validity. I argue, with reference to the work of social research methodologist Donald Campbell and colleagues, that it is both possible and desirable to meld research validity and rhetoric in furthering our understanding of the policy-making process.