Last update:
07-Dec-2017

Qualitative research is the primary research tool in social sciences. Recently it is being applied also in the health sciences, either independently or in combination with quantitative research, in order to achieve more reliable and valid conclusions. Qualitative research usually precedes quantitative research in research fields with limited knowledge. In such cases, the researchers can derive information to help them to understand in depth the research questions, based on which they can develop new research hypotheses to be examined by quantitative research methodology. Quantitative research investigates relationships between variables under study, while qualitative research explains and interprets these relationships, searching for causes. Qualitative research can also investigate and interpret in depth various dimensions of human beliefs, behavior, attitudes, perceptions, experiences, values, opinions and knowledge. Researchers should understand in depth the fundamental principles of the methodology of qualitative research in order to conduct studies with low bias. In this paper, the fundamental principles of qualitative research in the health sciences are discussed, and in particular the differences between qualitative and quantitative research, and the methods of data collection, sampling methods and ethical issues. Data collection methods in qualitative research include observation, interviews, focus groups and the Delphi method. For qualitative research, the most frequent non-probability sampling methods used are convenience sampling, purposive sampling, quota sampling and snowball sampling. The essential ethical issues in qualitative research are respect for the participants, benefit and justice for the participants, protection of anonymity and the informed consent of the participants.

Key words: Data collection, Ethical issues, Methodology, Qualitative research, Sampling.