Qualitative research is an increasingly popular method of enquiry in biomedical, clinical and behavioural research. Once regarded as the preserve of social scientists and psychologists, qualitative methods have entered the mainstream of epidemiology and clinical research, as evidenced by the publication of a series of papers in the British Medical Journal (Britten 1995; Mays and Pope 1995; Pope and Mays 1995; Pope et al. 2000). The qualitative methods to be described in this chapter offer a scientific approach to understanding and explaining the experiences, beliefs, and behaviour of defined groups of people. The contrasting features and the complementary roles of qualitative and quantitative methods of enquiry will be described.
While the majority of chapters in the present volume are concerned with research methods designed to answer questions such as ‘how many?’ or ‘how frequently?’, qualitative methods enable us to explore the ‘why?’, ‘what?’, and ‘how?’ of human behaviour. Since the aim is to understand the meaning of the phenomena under study from the perspective of the individuals concerned, the direction of enquiry is guided more by respondent than researcher. This approach is particularly appropriate to complex phenomena such as the range of beliefs that underlie illness behaviour and the aspects of health care that matter to different service users. Qualitative enquiry would focus on identifying beliefs and describing the circumstances that surround particular behaviours, while quantitative research would focus on measurable characteristics of the sample and the frequency and outcome of their behaviour.
An example of the contribution of the two methodological approaches is the study of variations in treatment of depression in older people. Epidemiological studies in the community and in primary care settings have found that the prevalence of depression in older adults far exceeds the prevalence of the disorder among those consulting their general practitioners. To identify the factors associated with this disparity, qualitative researchers would set out to explore the reasons why older people with depression do and do not present their symptoms to the GP. The aim would be to describe the range of beliefs about depression among attenders and non-attenders. The quantitative approach would involve establishing the strength of associations between personal characteristics, external factors, and behaviour of older people with depression. It is clear from this example that both approaches are complementary in identifying the nature of the disparity.
Qualitative research is based on the premise that each individual's experience is unique and the beliefs that underlie illness behaviour can only be measured once identified and described from a variety of individual perspectives. When information of this type is combined with data on prevalence and variable risk, more appropriate services and outcome measures can be developed.
Causal Analysis as a Bridge Between Qualitative and Quantitative Research
