Objectives: To highlight some of the practical problems associated with trying to combine qualitative and quantitative evidence in Cochrane systematic reviews.

Methods: Data and experiences derived from conducting a Cochrane Dementia and Cognitive Impairment Group review on supportive interventions for caregivers of people with Alzheimer's disease will be used to show the practical difficulties and possible solutions in attempting to combine qualitative and quantitative material in the same review. The paper builds on a previous poster exhibited at the Baltimore Colloquium which highlighted the theoretical possibilities of combined reviews.

Results: The process of updating the underlying review for this paper has uncovered both new clinical trial and qualitative material. Conventional search techniques often fail to pick up relevant qualitative material (which gives valuable insight into appropriateness as well as effectiveness) this paper offers some pointers on how to improve searching for such material. In adopting the 'enhancement' approach to combining the two forms of data the paper shows how incorporating qualitative material need not compromise the tried and tested techniques of the Cochrane Collaboration with regard to minimising bias. Specifically, it points to the role of qualitative findings as challenging counter-positions for exploring often weak quantitative results in structured discussion review sections. Moreover, it discusses the appraisal of qualitative material and dealing with the interpretative nature of qualitative research reporting.

Discussion: Qualitative material is a valuable offshoot of many trials and combining such material offers useful clues as to the appropriateness of clinical effectiveness as well as in the interpretation of inconclusive trial results. The theoretical benefits of combination are widely known but what is not so clear are the practical strategies that can be deployed to promote these - this paper highlights those real-life strategies.