Intersection of epidemiology, clinical medicine, and qualitative research

Contemporary research is dominated by big data, machine learning, and –omics. There is an increasing interest and engagement of researchers around revealing new evidence using big data for machine learning and –omics research. A possible reason for this phenomenon is that the focus of population health and clinical research has been mainly on evidence-based approaches or approaches that address causal inference. In fact, in the pyramid of evidence-based research, systematic reviews and meta-analysis of randomised controlled trials (RCT) epitomise the highest quality of evidence (sometimes referred to as the gold standard of evidence in health care). Hence, this evidence forms the pinnacle of the pyramid followed by evidence from individual RCTs and observational studies. In this pyramid which is primarily based on methodological merits of study designs, a method that has been assigned ‘low level of evidence’ is qualitative method which sometimes lead to questions regarding legitimacy of qualitative research (Lester & O’Reilly, 2015).


Clinical research mainly focuses on assessing the efficacy and effectiveness of drugs or interventions whereas epidemiology revolves around the study of frequency and determinants of diseases in populations. Mostly, this is accomplished by conducting randomised controlled trials or observational studies in selected populations or undertaking secondary data analysis of administrative datasets. However, these studies are limited in situations where one has to unravel barriers and facilitators for certain behaviours, experiences, or opinions that cannot be captured by quantitative research alone.


Qualitative research frequently involves the use of theories to assist methodology to answer the research question/s. A variety of methods such as focus group interviews, ethnography, journey mapping, and photovoice can be used to answer the research question/s. 

For instance, a researcher focusing on quantitative research can enumerate reasons for non-adherence to a specific treatment or intervention in a survey questionnaire or ask open-ended questions about the reason/s for non-adherence. However, qualitative research methodology such as journey mapping can allow one to visualise the journey of the participant and get an overview of their experience during their entire care journey which can enable the clinician/researcher to unravel the cause/s of non-adherence from the patient’s point of view. Another example is that of a researcher who conducts research in a community or subpopulation based on preconceived knowledge or past research about the main problem facing the community/subgroup. Focus group interviews, direct observations, and key stakeholder interviews can enable to understand the main issues facing the community and not issues perceived by the researcher which can save substantial time, money, and effort for both the funder and researcher as well. For instance, using the diffusion of innovation theory and qualitative research methods one can find the early adopters or laggards for a specific intervention in a specific population which may then necessitate different strategies for the adopters and laggards in the population for successful implementation.


Banniester-Tyrrell & Meiqari (2020) have reported that qualitative research enables one to add context to health-related outcomes. They have stated that it is possible to assess the effects of ‘social roles, structures, and processes on health-related outcomes and their trajectories’ using qualitative methods which will enable us a deeper understanding of determinants of diseases in populations. Qualitative research entails involvement of research participants (participatory action research) –especially their point of view- which can inform what is important and why it is important. Besides this, one can conduct mixed methods research wherein a quantitative component is added to qualitative research or vice-versa to examine the question from different viewpoints. It can enable hypothesis generation that can be tested in larger populations and analysed using quantitative methods. Qualitative and mixed methods research has a greater role to play in the current funding schemes especially with prominent emphasis by funding bodies on patient and public involvement in research.


Rema Ramakrishnan is CSOR EXPRESS Senior Statistician at the National Perinatal Epidemiology Unit (NPEU)



Banniester-Tyrrell M, Meiqari L. (2020). Qualitative research in epidemiology: theoretical and methodological perspectives. Annals of Epidemiology, 49, 27-35

Lester J, O’Reilly M. (2015). Is Evidence-Based Practice a Threat to the Progress of the Qualitative Community? Arguments from the Bottom of the Pyramid. Qualitative Inquiry, 21(7), 628-632.