Modeling economic evaluations of pharmaceuticals: Manipulation or valuabletool?

Controversy surrounds the use of models in economic evaluations of pharmace uticals. Many believe that modeling is a way of manipulating results and is not credible, whereas others consider modeling a valuable tool in economic evaluations. The purpose of this article is to provide a historical perspe ctive on modeling, focus on the controversy and policy implications of usin g models, and review the suggested framework and guidelines for modeling pr actices. Models can be used to extrapolate beyond intermediate end points, predict costs and consequences of alternative therapies, generalize data to other settings, pose questions instead of providing answers when no data e xist, design an evaluation to reduce uncertainty, and perform direct compar isons that are not currently available. We believe that a useful model shou ld document the detailed inner workings, assumptions, and inherent bias dur ing production (and at publication time), so that its reviewers and users c an evaluate the appropriateness of the model's outcomes. The acceptability of models in the future rests with the researchers constructing them. If co nstructed appropriately, modeling economic evaluations is not a manipulatio n but rather a valuable tool.