Including qualitative research in systematic reviews: opportunities and problems

Qualitative research has been increasingly recognized in recent years as ha ving a distinctive and important contribution to make to health care resear ch. It is capable of being used as a methodologically sufficient approach i n its own right, as a precursor to quantitative studies, during or after tr ials to explain processes and outcomes, and as a means of enhancing the lin k between evidence and practice. However, qualitative research has been lit tle used as an evidence resource for systematic reviews. We argue that form al synthesis of both qualitative and quantitative forms of research is esse ntial, and we discuss some of the problems that need to be overcome in carr ying out such syntheses. These include methodological prejudice, problems i n searching for qualitative evidence, and issues in synthesizing qualitativ e data. We call for progress to be made on the science and methods of inclu ding qualitative research in the evidence base of medicine.