[Qualitative methods in medical research--preconditions, potentials and limitations].

Qualitative research methods are appropriate for description and analysis of properties, contents, or experiences in the field of medicine. Textual data are drawn from interviews, observations, or written material. In the analysis, raw data are transformed into findings by interpretation and summarization of the material. Qualitative research methods employ well-known presumptions from the theory of science that are assumed to lead to systematic and reflexive construction of knowledge. The process is supposed to be accessible and contestable, and findings are supposed to reach beyond the local study context. Assessment of scientific quality is not confined to quantitative studies. Criteria such as relevance, validity, and reflexivity are proposed. Reflexivity deals with the presumptions surrounding the research process that play a part in shaping the results. The medical researcher who wants to apply qualitative methods must learn to handle the impact of the researcher's role, presumptions and consequences of sampling, and systematic organization and interpretation of the material. These are, however, challenges that must be overcome in all scientific pursuits, irrespective of the type of data used.