Afzali Hossein Haji Ali, Karnon Jonathan
School of Population Health, The University of Adelaide, Level 7, 178 North Terrace, Adelaide, SA, 5000, Australia,
Pharmacoeconomics. 2015 May;33(5):435-43. doi: 10.1007/s40273-015-0256-0.
Given the inherent uncertainty in estimates produced by decision analytic models, the assessment of uncertainty in model-based evaluations is an essential part of the decision-making process. Although the impact of uncertainty around the choice of model structure and making incorrect structural assumptions on model predictions is noted, relatively little attention has been paid to characterising this type of uncertainty in guidelines developed by national funding bodies such as the Australian Pharmaceutical Benefits Advisory Committee (PBAC). The absence of a detailed description and evaluation of structural uncertainty can add further uncertainty to the decision-making process, with potential impact on the quality of funding decisions. This paper provides a summary of key elements of structural uncertainty describing why it matters and how it could be characterised. Five alternative approaches to characterising structural uncertainty are discussed, including scenario analysis, model selection, model averaging, parameterization and discrepancy. We argue that the potential effect of structural uncertainty on model predictions should be considered in submissions to national funding bodies; however, the characterisation of structural uncertainty is not well defined within the guidelines of these bodies. There has been little consideration of the forms of structural sensitivity analysis that might best inform applied decision-making processes, and empirical research in this area is required.
鉴于决策分析模型产生的估计值存在内在的不确定性，基于模型的评估中的不确定性评估是决策过程的重要组成部分。尽管人们注意到模型结构选择的不确定性以及做出错误的结构假设对模型预测的影响，但澳大利亚药品福利咨询委员会（PBAC）等国家资助机构制定的指南中，对这类不确定性的特征描述相对较少。缺乏对结构不确定性的详细描述和评估可能会给决策过程增加更多不确定性，对资助决策的质量产生潜在影响。本文总结了结构不确定性的关键要素，阐述了其重要性以及如何进行特征描述。讨论了五种描述结构不确定性的替代方法，包括情景分析、模型选择、模型平均、参数化和差异分析。我们认为，在向国家资助机构提交的材料中应考虑结构不确定性对模型预测的潜在影响；然而，这些机构的指南中对结构不确定性的特征描述并不明确。对于哪种结构敏感性分析形式最能为实际决策过程提供信息，几乎没有进行过考虑，因此需要在这一领域开展实证研究。
