Introduction: As considered in the rest of this volume, the effects of the IDEFICS intervention on obesity rates were not encouraging. This paper considers how far findings from the IDEFICS study and similar intervention studies are relevant to the policy process and political decision-making. Methods: The paper offers theoretical and policy-level arguments concerning the evaluation of evidence and its implications for policymaking. The paper is divided into three parts. The first considers problems in the nature and applicability of evidence gained from school- and community-level obesity interventions. The second part considers whether such interventions present a model that policy-makers could implement. The third part considers how we should think about policy measures given the limited evidence we can obtain and the many different goals that public policy must take account of. Results: The paper argues that (1) there are clear reasons why we are not obtaining good evidence for effective school- and community-level interventions; (2) public policy is not in a good position to mandate larger-scale, long-term versions of these interventions; and (3) there are serious problems in obtaining ‘evidence’ for most public policy options, but this should not deter us from pursuing options that tackle systemic problems and have a good likelihood of delivering benefits on several dimensions. Conclusions: Research on school- and community-level obesity interventions has not produced much evidence that is directly relevant to policymaking. Instead, it shows how difficult it is to affect obesity rates without changing wider social and economic factors. Public policy should focus on these
