Qualitative research has an enormous amount to contribute to the fields of health, medicine and public health but readers and reviewers from these fields have little understanding of how to judge its quality. Work to date accurately reflects the complexity of the theoretical debate required but may not meet the needs of practitioners attempting to apply qualitative work in reviews of evidence. This article describes a simple, practitioner-focused framework for assessing the rigour of qualitative research that attempts to be inclusive of a range of epistemological and ontological standpoints. An extensive review of the literature, contributions from expert groups and practitioners themselves lead to the generation of two core principles of quality: transparency and systematicity, elaborated to summarize the range of techniques commonly used, mirroring the flow of the research process. The complexities discovered are only summarized here. Finally, outstanding issues such as 'how much transparency is enough?', are flagged up.