Qualitative studies. Their role in medical research.

OBJECTIVE: To define qualitative research in terms of its philosophical roots, the questions it addresses, its methods and analyses, and the type of results it can offer. DATA SOURCES: MEDLINE and CINAHL (Cumulative Index to Nursing and Allied Health Literature) databases were searched for the years January 1985 to April 1998. The search strategy consisted of "textword" terms that searched in the "title" field of both databases. Qualitative research and evaluation textbooks in health and the social sciences were also used. QUALITY OF EVIDENCE: The information on qualitative research is based on the most recent and valid evidence from the health and social science fields. MAIN MESSAGE: Qualitative research seeks to understand and interpret personal experience to explain social phenomena, including those related to health. It can address questions that quantitative research cannot, such as why people do not adhere to a treatment regimen or why a certain health care intervention is successful. It uses many methods of data collection, including participant observation, case studies, and interviews, and numerous approaches to data analysis that range from the quasistatistical to the intuitive and inductive.
CONCLUSIONS: Qualitative research, a form of research completely different from quantitative research, can provide important insights into health-related phenomena and can enrich further research inquiries.