Experiences of structured elicitation for model based cost-effectiveness analyses

Empirical evidence supporting the cost-effectiveness estimates of particular health care technologies may be limited, or it may even be missing entirely. In these situations, additional information, often in the form of expert judgements, is needed to reach a decision. Formal methods to quantify experts’ beliefs, termed structured expert elicitation (SEE), but only limited research is available in support of methodological choices. Perhaps as a consequence, the use of SEE in the context of cost-effectiveness modelling is limited. This paper reviews applications of SEE in cost-effectiveness modelling with the aim of summarising the basis for methodological choices made in each application and record the difficulties and challenges reported by the authors in the design, conduct and analyses. This review of experiences of SEE aimed to highlight a number of specificities/constraints that can shape the development of guidance and target future research efforts in this area. The review demonstrates considerable heterogeneity in methods used and authors acknowledge great methodological uncertainty in justifying their choices. Specificities of the context area emerging as potentially important in determining further methodological research in elicitation are: between-expert variation and its interpretation, the fact that substantive experts in the area may not be trained in quantitative subjects, that judgements are often needed on a variety of parameter types, the need for some form of assessment of validity, and the need for more integration with behavioural research to devise relevant debiasing strategies.