Drug benefits policy-making for seniors in British Columbia has been increasingly influenced by research since 1993. The "evidence-based medicine" paradigm, which emphasizes the primacy of direct evidence from randomized control trials, inspired key policy-makers and influenced policy concerning coverage of new and existing drugs. New drugs, if more expensive than existing similar drugs, are not covered unless published randomized control trials show superior effectiveness. Indirect evidence of effectiveness, based on surrogates, is given less weight, and non-randomized studies are rarely considered. Evidence of cost-effectiveness of new drugs is reviewed separately. For existing drugs, a new reimbursement policy, Reference Based Pricing (RBP), was introduced, based on both direct and indirect evidence of comparative effectiveness of drugs. Implementation of RBP was complex and necessarily rapid, which meant that independent systematic review of evidence relevant to implementation issues was infeasible, particularly in regard to rapid prior authorization of exemptions to RBP. Contrasts between the processes for new and existing drugs provide insights into the difficulties of applying the idea of direct evidence-based policy-making in practice.