Strengths and weaknesses

Qualitative methods tend to collect very rich data in an efficient manner: rather than being limited to the responders to a set of pre-defined questions, it is possible to explore interesting concepts that can lead to novel theory by analysing the entirety of a participant’s interview/story/interaction.
Qualitative methods can lead to the generation of new theory from unexpected findings that go against “conventional” public health understanding
When combined with quantitative methods, qualitative research can provide a much more complete picture. For example, a well-designed process evaluation of a trial may provide important insights into participant attitudes, beliefs, and thoughts about the intervention and its acceptability, which may not be evident from the quantitative outcome evaluation.

It is important that qualitative researchers adhere to robust methodology in order to ensure high quality research. Poor quality qualitative work can lead to misleading findings.
Qualitative research alone is often insufficient to make population-level summaries. The research is not designed for this purpose, as the aim is not to generate summaries generalisable to the wider population.
Policy makers may not understand or value the interpretive position and therefore may not recognize the importance of qualitative research.
Qualitative research can be time and labour-intensive. Conducting multiple interviews and focus groups can be logistically difficult to arrange and time consuming. Furthermore, tranalysanscription and analysis of the data (comparing, coding, and inducting) requires intense concentration and full immersion in the data – a process that can be far more time-consuming than a descriptive statistical analysis.