iweights in xtgee

[Deborah Donnell]

I am unable to find documentation of the details of the computation when iweight is used with xtgee. Can someone elucidate or point me to the documentation?

[Richard Williams]

Section 20.23.4 of the User's guide discussed weights. Among other things it says iweights are generally inserted into calculation formulas in the same way as fweights. iweights do not need to be integers.

Why do you want to use iweights? I think it is unusual for the user of a program to want to specify them.

[Deborah Donnell]

Each of my observations is a mean response from a facility, where the number of people in each facility varies from 100 to 2000. I do not have access to individual level data. I have observations over 5 quarters, and observations within each facility are correlated over time. I want to estimate the person level change in probability of response associated with a treatment randomized at the facility level, thuse want to conduct a weighted analysis. I would just like to understand what stata is actually doing when you use iweights.