Comparison of methods for generating quality of live items: individual interviews versus focus groups

Works centered on the search for a quality of life (QoL) definition have mostly privileged the individual interviews. No methodology has compared yet the quantitative production of items resulting from individual interviews with those from focus groups, concerning a lower limbs osteo-arthritis QoL. Purpose: To compare methods of item generation for methods : 2 individual interviews and 2 focus groups and to identify the pertinence of a theoretical construit of QoL. Methods: All methods compared relied on extraction of verbatim collected during tape recorded interviews, transcripted and analysed by 3 teams of health psychologists and sociologists independently. The 4 methods compared were interviewed with interview guide with OA patients in 1) focus group, 2) individual semi-structured interview and 3) using a cognitive interview technique to enhance memories. Using the final scale as a gold standard, the sensitivity and specificity, i.e. the contribution of each method to the scale, were estimated. Results: 66 individual and focus interviews were conducted with 96 OA patients. After exclusion of speeches not related to QoL (i.e. satisfaction, coping, locus of control), 80 items were identified relevant. With patients, focus group produced 74% of the items, while both individual methods contributed 100% of resulting items and none item except subject. Focus group methods contributed some themes but individuals gave more in depth information. Traditional semi-structured interviews contributed to known QoL themes and to items on the feeling of being embarrassed for people to be seen, to ask for help and to annoy close relatives, while cognitive interviews provided more fine tuned items on exchanges with and perception by others about their condition, as well as perspective in life and fears from future dependency. Conclusion. The selected method is relevant to explore the theoretical construit of QoL. One can recommend to use patients’ semi-structured interviews with a traditional or a cognitive technique, conducted by interviewers preferably non-specialist of the condition explored. Perspectives. The question is then what is the influence of the topic on the method to be retained?