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st: Generating a nested case-control study

From   "Cornelia Zekveld" <>
Subject   st: Generating a nested case-control study
Date   Wed, 09 Feb 2005 13:41:49 +0000

Dear statalisters,

I have an occupational cohort (n=866, cases=222) and would like to generate cases and controls from the data. I'd like to have as many controls as possible, with the two requirements:

1) The control must have been employed when the employee became a case (risk set sampling)
2) The control must have started employement around the same time as the case (up to 6 months before but not after).

It is also OK to use, as a control, someone who becomes a case at a later time.

I have come across the command -sttocc- but it only takes care of the first requirement. I do not know how to incorporate the second constraint into the command.

Are there other stata commands that I'm not aware of that will be of help here?

Also, I want to know whether -sttocc- samples the controls with replacement?
It seems to be the case sine I have set the option number(#) to 30, just to see what happens and it was possible to generate 30 controls for each case - which seems odd given the cohort sample size.

Is it possible that a subject can be a control for more than one case? Is there anything wrong with this?

Any help will be greatly appreciated!!

Thank you,

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