Few will doubt the need for robust systematic research methods to underpin evidence for policy interventions. Recently, systematic reviews of randomised controlled trials have gained popularity as a source of knowledge for 'evidence based policy'. Relying on one research method, however, is unlikely to provide a comprehensive research base for policy-making. This presentation explores why other research methods are needed. A framework is proposed for assessing research for evidence based policy, using quantitative and qualitative methods method and citing examples from the Cochrane Database of Systematic Reviews. Systematic reviews on health policies provide the first step, summarising current knowledge and benefit of complex interventions. Further RCTs are usually required to fill gaps in knowledge, particularly cost effectiveness and patient centred outcomes. This should be complemented with qualitative research, to identify and unpack what works in 'black box', and to assess patient and carer's preferences. Finally, policy decision-making relies on values, priorities and resources as well as evidence, and ethical research provides the essential link between knowledge and implementation. In summary, this framework provides a model for systematically combining the results of quantitative and qualitative research essential for implementing evidence-based policy.