Hello all
I am trying to write a programme that will run a command sequentially
for observations of an individual. For each individual I have multiple
spells and multiple failures. However, the twist is that I also need
to exclude a period of time at risk after each treatment (prophylaxis)
and after each failure (to prevent double-counting of failures that
may actually be the same episode). I managed to do this without any
problem for the treatment, but if an episode is disqualified (by a
prior treatment or episode) I don't want it to disqualify a subsequent
episode. Therefore I need to run the code sequentially for each spell
of an individual, but using the marksample touse code to run it "by"
individual doesn't seem to be working - the "forvalues" seems to
always interpret _N as the last observation in the whole dataset, not
the last observation for each individual.
I have the following code:
program define byid, byable(recall, noheader)
marksample touse
sort `id' `start'
if `touse' {
forvalues i = 1(1)`=_N' {
replace lagend = (`end' + `lag') if ((`tx' > 0 & `tx' < .) | (`case'
> 0 & `case' < .))
drop if lagend[`i'-1]>`end' & `id'[`i'-1]==`id'
}
}
end
gen lagend=.
qui by id: byid
but I get the error:
2nd by group not found
r(111);
And the programme isn't doing what I need it to.
Any ideas?
Ilona
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