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st: Using -sampsi- for clustered observations


From   Ted White <seahorsebear@yahoo.com>
To   statalist@hsphsun2.harvard.edu
Subject   st: Using -sampsi- for clustered observations
Date   Fri, 27 Feb 2009 16:40:57 -0500

Hi, all. I need to do a power calculation for a study that will contain two levels of clustering; there will be repeat dichotomous outcomes for individuals who will be clustered within families. While the documentation shows to use post() to specify the number of repeat outcomes in a dataset, I'm left with two questions:

1) What if the number of repeat observations will vary by respondent? I have a postulated distribution for the number of observations that will take place.

2) How to handle nesting by family in the power calculation?

If this isn't handled by -sampsi- it seems that I could do a series of simulations. But I'd feel pretty silly doing that if there's a simpler method that I don't know about.

Thanks!

Ted White
Yale University Center for Interdisciplinary Research on AIDS
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