Reviewing the evidence used in cost-effectiveness models in health technology assessment: a qualitative investigation of current concerns and future research priorities

Objectives: Health technology assessments typically include a systematic review of clinical efficacy evidence and a cost-effectiveness model. The development of the model always requires additional information beyond clinical efficacy. Depending on the timing, size and number of information requirements, the researcher faces considerable difficulties ensuring that reviewing activity to inform model development is both timely and systematic. There is a tension in terms of the need to ensure that this process is transparent and reproducible. This paper uses qualitative methods to identify these issues and to explore options for their resolution. Methods: A focus group was held with 1 7experienced systematic reviewers, information specialists and health economic modellers. Framework analysis was used to analyse themes within the qualitative data. Results: Six key themes were identified including: 1) problem structuring, 2) current practice, 3) adequate information, 4) timing, 5) ideal practice and 6) areas for further research. Reviewing, searching and modelling were seen as integrated tasks and the respondents felt that the whole team should be involved in structuring the decision problem. Good communication was deemed to be essential with more time spent on the most important information requirements. Assessments of the quality and relevance of information were also considered important by the focus group members. Future research needs include training for focussed searching, problem structuring, quality assessment and the validation of parameter estimates. Conclusions: This preliminary investigation highlights numerous concerns and potential deficiencies in the process of identifying, selecting and using evidence to inform models. Further guidance is required to ensure that such research activity is transparent, timely and rigorous