SAMPLE-SIZE JUSTIFICATION IN PHASE III IV CLINICAL-TRIALS/

A sample size justification is often a key component in securing fundi ng to conduct a clinical trial. Sample size computations typically req uire supplying values of parameters that are unknown and subject to mi sspecification. As an alternative, we advocate a power analysis approa ch based on a range of reasonable values for such parameters. We illus trate this approach in the context of a secondary stroke prevention tr ial.