Sample size determination for equivalence test using rate ratio of sensitivity and specificity in paired sample data.

Department of Mathematical and Computer Sciences, San Diego State University, San Diego, CA 92182, USA. kjl@rohan.sdsu.edu

Before implementing a new diagnostic test, we may wish to study whether this test is noninferior to a reference test with respect to the sensitivity and/or the specificity. This paper discusses sample size determination for one-sided equivalence (or noninferiority) testing of the rate ratio using paired-sample data. Using large sample theory, this paper derives asymptotic sample size formulae for the required number of subjects giving a desired power 100(1 - beta)% at a specified alpha-level. To evaluate the accuracy of these formulae, this paper considers several test statistics and uses Monte Carlo simulation to estimate the corresponding type I error and power with the given resulting sample sizes in a variety of situations. Finally, this paper notes those situations for which the asymptotic sample size formulae developed here are of limited use and suggests a simple empirical adjustment to alleviate this limitation.

PMID: 11514039 [PubMed - indexed for MEDLINE]