Many countries have centralized the clinical and economic assessments necessary for evidence-based drug coverage policy. We analyze such processes in Australia, Canada, New Zealand, and the United Kingdom. These countries apply comparable approaches to the assessment and appraisal of evidence but apply the processes to different types of drugs and use the reviews within different decision-making contexts. Review processes applied to all medicines and clearly tied to coverage decisions appear to influence national drug use. Rigor of process and transparency of data and rationale are believed to be important for maximizing the impact and political acceptability of the processes.