Sample size formulas for estimating intraclass correlation coefficients with precision and assurance
Article first published online: 4 JUL 2012
Copyright © 2012 John Wiley & Sons, Ltd.
Statistics in Medicine
Volume 31, Issue 29, pages 3972–3981, 20 December 2012
How to Cite
Zou, G. Y. (2012), Sample size formulas for estimating intraclass correlation coefficients with precision and assurance. Statist. Med., 31: 3972–3981. doi: 10.1002/sim.5466
- Issue published online: 23 NOV 2012
- Article first published online: 4 JUL 2012
- Manuscript Accepted: 15 MAR 2012
- Manuscript Received: 19 NOV 2011
- confidence interval;
The number of subjects required to estimate the intraclass correlation coefficient in a reliability study has usually been determined on the basis of the expected width of a confidence interval. However, this approach fails to explicitly consider the probability of achieving the desired interval width and may thus provide sample sizes that are too small to have adequate chance of achieving the desired precision. In this paper, we present a method that explicitly incorporates a prespecified probability of achieving the prespecified width or lower limit of a confidence interval. The resultant closed-form formulas are shown to be very accurate. Copyright © 2012 John Wiley & Sons, Ltd.