A new test of non‐inferiority for anti‐infective trials

This paper describes a new statistical test of non‐inferiority in clinical trials of anti‐infective medications. The test allows the inferiority limit, delta, to vary with the underlying success rates. The test is a simple modification of the standard fixed‐delta test, and its parameters can be adjusted to yield the fixed‐delta test, a test similar to the FDA's Points‐to‐Consider procedure, or a test with nearly constant power values over a range of success rates. The test satisfies the size and power criteria for a valid statistical test. The effects on the test of lowering success rates through stringent criteria or through error are discussed. Copyright © 2002 John Wiley & Sons, Ltd.