(adsbygoogle = window.adsbygoogle || []).push({}); So if I have a study where people are randomized within treatment sites do I always have to have the site indicator in the regression equation?

This text(Homsler and Lemmeshow 2nd ed) says yes.

Here is some context provided below.

And here is the output for the multivariate equation after univariate analysis has indicated that how to build the multivariate model

Now the usual strategy is simply to drop variables that are not statistically significant.

They said that because SITE is randomized, we cannot drop it. Why? It wasn't explained in the text.

Is it because it is a potential confounder? But clearly from the pval, we don't see it associated with the outcome. So it doesn't seem to confound anything.

What is different about site in this study than about a study simply randomizing something into two treatment groups where there is only one site to begin with ?

What is different about site than a regular indicator variable describing dichotomy? I know it has something to do with the randomization within site, but I don't get it at a gut level

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# A Keeping Randomized Variable in Regression?

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