stratified sampled analysis

[gregoepi]

Hi,
I have a data set obteined by a stratified sampling in a cross sectional study.

I want to perform logistic regresion analysis however I am not sure how I should accout for the stratification of my dataset.

By the way I am using STATA

Thanks.

 

[fed1]

It depends a bit on how the strata are defined.

I am of school of thought that you should place stratum as a covariate in the model. possibility of interaction with stratum. If it is your covariates that define the strata then no alteration is necessary. Ive seen more complicated discussions on the matter, but this is my no nonsense approach.

It is because you are estimating

E(Y given covariates)

If the covariates define the strata, then it is the same as estimating the average in each strata, which is exactly what you are going to end up with anyway.

 

[gregoepi]

As it is a proportional stratified ramdom sampling. It would still be enough only with include the variable that define the strata in the model?

 

[gregoepi]

any comments? It getting urgent