Scientific Publications by FDA Staff
Biometrical J 1997;39(3):327-37
Significance Levels of Randomization Trend Tests in the Event of Rare Occurrences
Chen JJ, Kodell RL, Pearce BA
In the statistical evaluation of data from a dose-response experiment, it is frequently of interest to test for dose-related trend: an increasing trend in response with increasing dose. The randomization trend test, a generalization of Fisher's exact test, has been recommended for animal tumorigenicity testing when the numbers of tumor occurrences are small. This paper examines the type I error of the randomization trend test, and the Cochran-Armitage and Mantel-Haenszel tests. Simulation results show that when the tumor incidence rates are less than 10%, the randomization test is conservative; the test becomes very conservative when the incidence rate is less than 5%. The Cochran-Armitage and Mantel-Haenszel tests are slightly anti-conservative (liberal) when the incidence rates are larger than 3%. Further, we propose a less conservatived method of calculating the p-value of the randomization trend test by excluding some permutations whose probabilities of occurrence are greater than the probability of the the observed outcome.
|Category: Journal Article|
|Includes FDA Authors from Scientific Area(s): Toxicological Research|
|Entry Created: 2012-12-26|