A SEQUENTIAL PROCEDURE TO TEST THE PROGRESSIVE DECREASE OF RARE ADVERSE EVENTS

A program to construct the Rapid Sequential Test (R-ST), a sequential procedure to test the decrease of the rate of rare adverse events, is described. This sequential procedure is constructed with the Sequentia l Probability Ratio method. It relies on a model for the progressive d ecrease in the rate of adverse events from a given initial rate to a t arget rate, during a transition period. The program allows one to calc ulate the bounds of rejection of the R-ST, and to study its power unde r various types of decrease. It is shown that the R-ST gives a conclus ion faster than standard sequential procedures for the same type I and II error, saving at least one quarter of the trials completed during the transition period. The use of the software to construct R-STs is d iscussed with respect to the specification of the model. Copyright (C) 1996 Elsevier Science Ltd.