[R] probit analysis for correlated binary data

[Thomas Lumley]

On Wed, 24 Sep 2003, Law, Jacqueline {Regu~Pleasanton} wrote:

> Dear all,
>
> I have a question on the dose-response estimation with clustered/
> correlated binary data. I would like to estimate the hit rate for a
> certain test at various concentration levels. The test is used on 5
> subjects, and each subject is tested 20 times. If we assume that the 100
> samples are independent, the hit rate estimate is unbiased, but the
> variance is under-estimated. The other estimate of interest is the
> concentration that will give a 95% sensitivity of the test. I suppose
> the same problem would occur if a probit model is fitted to the data and
> assume all the samples are independent. Does anyone have any suggestions
> on how to analyze this kind of data?
>

I think you want a GEE, see the `gee' and `geepack' packages.

	-thomas