Last update:
13-Jan-2026

Applied research is commonly categorized into qualitative and quantitative research. Qualitative research is primarily exploratory, aiming to achieve an in-depth understanding of complex and multidimensional concepts and phenomena, such as behaviors, emotions, perceptions, thoughts, and opinions. Quantitative research focuses on measuring study characteristics and phenomena, followed by statistical analysis. Measurement plays a critical role, as it links empirical observations to mathematical expressions or equations. Both approaches are widely employed in health sciences, either complementarily or independently. They may address the same research question to enhance validity or investigate different questions using distinct methodologies. These differences primarily concern (a) the overall framework, (b) the research focus, (c) the form of questions, (d) the type of data collected, and (e) flexibility in design. Data collection methods in qualitative research differ significantly from those in quantitative research and mainly include (a) observation, (b) interviews, (c) focus groups, and (d) the Delphi method. In qualitative research, the most common non-probability sampling methods are (a) convenience sampling, (b) purposive sampling, (c) quota sampling, and (d) snowball sampling.

Key words: Delphi method, Ethical issues, Focus groups, Qualitative research, Quantitative research, Sampling methods.