Abstract

The elicitation of probability distributions from experts can be used as away to characterise parameter uncertainty in decision models, when evidence isscarce. This approach has been used routinely for a long time in fields likeecology or risk assessment, but it can also be helpful in decision models built aspart of health technology assessments.Eliciting probability distributions from experts is a complex process, andmany aspects of the elicitation process may influence the outcome. The generalliterature on elicitation of probability distributions proposes many elicitationmethods, but at the same time, suggests that different approaches may lead todifferent results, without defining a clear way of choosing among thesemethods. In the context of health technology assessment, elicitation ofprobability distributions is an even rarer topic and there is almost no guidanceon what is achievable or what the methodology to achieve it is.The aim of this PhD thesis was to explore elicitation of probabilitydistributions to estimate parameter uncertainty in decision models developed aspart of health technology assessments from a practical point of view, thatconsidered potential methodological trade-offs between minimising the risk ofbias and minimising the resources used for elicitation. Four studies were conducted as part of this project:1. A systematic review of current use of elicitation of probabilitydistributions reported in a health technology assessment context.2. A comparative study of two elicitation methods used to estimateparameter uncertainty in a health economic decision model.3. A comparative study exploring the feasibility of conductingelicitation remotely.4. A study exploring five different approaches to weighting individualexperts when mathematically aggregating probability distributions from severalexperts.This thesis covers the findings of these four studies, as well as attemptsto integrate this research in the greater context of health technologyassessment. By wider dissemination of methodological and practical issues ofelicitation in health technology assessment, they could be more clearlyanalysed in further research. Furthermore, this will help to increased confidencein the feasibility of conducting elicitation in the context of HTA.

Document Type

Thesis

Publication Date

2015

Embargo Period

2024-07-19

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