Sample Size for Independent Case-control Studies


Menu location: Analysis_Sample Size_Independent Case-Control.


This function gives the minimum number of case subjects required to detect a real odds ratio or case exposure rate with power POWER and two sided type I error probability ALPHA. This sample size is also given as a continuity-corrected value intended for use with corrected chi-square and Fisher's exact tests (Schlesselman, 1982; Casagrande et al. 1978; Dupont, 1990).


Information required


Practical issues


Technical validation

The estimated sample size n is calculated as:

- where α = alpha, β = 1 - power, ψ = odds ratio, nc is the continuity corrected sample size, m is the number of control subjects per case, and zp is the standard normal deviate for probability p. n is rounded up to the closest integer.



Copyright © 2000-2016 StatsDirect Limited, all rights reserved. Download a free trial here.