This article reports some findings from an investigation of social policy researchers in the UK. The findings relate to the quality criteria that social policy researchers deem to be appropriate to quantitative research, qualitative research and mixed methods research. The data derive from an e-survey of researchers which was followed up by semi-structured interviews with a purposively selected sample from among those e-survey respondents who agreed to be interviewed. The article emphasises the findings that relate to quality criteria for mixed methods research, since this is an area that has not attracted a great deal of attention. Greater agreement was found regarding the criteria that should be employed for assessing quantitative than qualitative research. The findings relating to mixed methods research point to a preference for using a combination of quantitative and qualitative research criteria and for employing different criteria for the quantitative and the qualitative components.