Fred Wolfe <[email protected]> demonstrates a problem
with -adjust-.
> Perhaps I am not understanding this correctly, but I get an error
> that I don't expect after adjust.
>
> . xi:xtgee zoster1 ra age65 sex,i(pat) robust eform fam(poisson)
> nolog exposure(exposure)
>
> <output cut>
>
> . adjust age65 sex,by(ra) exp ci
> offset (ln(exposure)) not constant within by()
>
> However,
>
> . tab exposure,m
>
> exposure | Freq. Percent Cum.
> ------------+-----------------------------------
> .5 | 92,635 100.00 100.00
> ------------+-----------------------------------
> Total | 92,635 100.00
>
> shows that the exposure is constant.
I have found the problem in -adjust- and will get a correction
into the next ado update.
Details for anyone interested:
When -adjust- looks at `e(offset)' it checks if the first 3
chars are "ln(" and if so it calls -substr()- to pull out from
`e(offset)' the string starting at the 4th position through to
all but the last. This call was formed incorrectly and was
leaving the last character, ")", in place. The code that
followed that then failed and caused the error message.
Ken Higbee [email protected]
StataCorp 1-800-STATAPC
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