How is uncertainty characterised in policy analysis and which approaches are relevant to health technology assessment (HTA)? A scoping review protocol

Uncertainty is inherent in any policy analysis, arising from natural randomness or variability, imperfect knowledge, and stakeholder interpretation of a system [1–3]. This is no different for health technology assessment (HTA), which is often applied as a tool to optimise the efficiency, equitability, and quality of universal health coverage schemes with constrained resources [4]. In HTA, for instance, uncertainty may arise through variation in outcomes between individuals, poor quality data and imperfect model structure, as well as through interpretation of the evidence by policy bodies and application of decision rules [5–9]. The way in which such uncertainty is analysed, communicated, and managed during the policy process can affect the decisions that are made [10]. Varying tolerance to uncertainty across HTA committees, for example, is thought to partly explain divergent medicine reimbursement decisions between European countries