18. Expert Elicitation to Inform Health Technology Assessment

In the face of constrained budgets, unavoidable decisions about the use of health care interventions have to be made. Decision makers seeking to maximise health for their given budget should use the best available information on effectiveness and cost-effectiveness, and for this purpose they may use a process of gathering and combining existing evidence in this context called Health Technology Assessment (HTA). In informing decisions, utilising HTA, expert elicitation can provide valuable information, particularly where evidence is missing, where it may not be as well developed (e.g. diagnostics, medical devices, early access to medicines scheme or public health) or limited (insufficient, not very relevant, contradictory and/or flawed). Here, formal methods to elicit expert judgements are preferred to improve the accountability and transparency of the decision making process, in addition to the important role in reducing bias and the use of heuristics. There have been a limited number of applications of expert elicitation in health care decision making, and in part this may be due to a number of methodological uncertainties regarding the applicability and transferability of techniques from other disciples, such as Bayesian statistics and engineering, to health care. This chapter discusses the distinguishing features of health care decision making and the use of expert elicitation to inform this, drawing on applied examples in the area illustrating some of the complexities and uncertainties.