Improving the Accuracy and Comparability of Model-Based Economic Evaluations of Health Technologies for Reimbursement Decisions: A Methodological Framework for the Development of Reference Models

Increasingly, decision analytic models are used within eco-nomic evaluations of health technologies (e.g., pharmaceut-icals) submitted to national reimbursement bodies in countries like Australia and UK, where such models play a fundamental role in informing public funding decisions. Concerns regarding the accuracy of model outputs and hence the credibility of national reimbursement decisions are frequently raised. We propose a framework for develop-ing reference models for specific diseases to inform eco-nomic evaluations of health technologies and their appraisal. The structure of a reference model reflects the natural history of the condition under study and defines the clinical events to be represented, the relationships between the events, and the effect of patient characteristics on the probability and timing of events. We contend tha