The concept of evidence-based policy and practice has many origins but its relation to the growth of the social sciences is arguably the most important. The uses of the social sciences for both understanding and transforming social policies and political systems has come to be assumed – complex and problematic though these may be. The concept is also closely linked with the concepts of globalisation, technological developments, and the ‘knowledge economy’. Thus the notions of ‘evidence’ and social science research have often been elided with political movements for social and economic change. In other contexts, these notions have been contextualised, so that ‘evidence’ and research are not deemed to be the same. Indeed, it is possible to argue that the notion of legal ‘evidence’ illustrates just how ideological it can be, how it can be used to marshal particular arguments and sustain a specific case rather than present it in a dispassionate manner.