# How to calculate sample size for comparing the area under the curve of two models?

Because I would like to calculate the sample size for comparing the area under the curve (AUC) of 2 models (cross-sectional study, predictor = continuous variable). Can you point me which function in R solves it.

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 +1 for a good question, as I'm also interested in this. Perhaps simulation? Irrespective of the solution, I'd like to see exactly how this was done. Or, perhaps a formula. – pmgjones Oct 3 '11 at 17:32

I could not find an R-package that would solve the problem. But I can remember reading the book "Statistical Methods in Diagnostic Medicine" by Zhou, Obuchowski and McClish (Amazon Link). They give a method (too long to reproduce it here for now) for determining the sample size and refer to 2 publications:

Obuchowski NA. Nonparametric analysis of clustered ROC curve data. Biometrics. 1997 Jun;53(2):567-78. PubMed PMID: 9192452.