I don't think you can refer to returned results in r() within the same
program as you create them as you do with:
scalar return difren=r(difren00) - r(difren91)
Maybe you should try to store each of the results in tempnamed scalars and
then calc the difference (into another tempnamed scalar) and then issue all
of the return scalar commands at the end.
Michael Blasnik
[email protected]
----- Original Message -----
From: "Fabio Soares" <[email protected]>
To: <[email protected]>
Sent: Wednesday, April 14, 2004 11:48 AM
Subject: st: problem with bootstrap in Stata 8.2
> Dear Statalisters,
>
> I�m running a difference-in-difference propensity score program using
logit
> and attnd commands and I didn�t manage to get the bootstrapped s.e. using
> the bootstrap command. Does anyone spot any mistake in the following code:
>
> capture program drop difatt
> program define difatt, rclass
>
> use favbar9100, clear
> drop if bairrinho==1 | nurb==1
>
> xi: logit fb dom91 agua91 esg91 lixo91 escm4_91 escm15_91 analf91 /*
> */ menor4_91 chmul91 up1sm_91 /*
> */ nmor91 mul91 chanalf91 amest_91 idade_91 ren_91
> i.RA
>
> predict pscore
>
> attnd rren_00 fb, pscore(pscore)
> scalar return difren00=r(attnd)
>
> attnd rren_91 fb, pscore(pscore)
> scalar return difren91=r(attnd)
>
> scalar return difren=r(difren00) - r(difren91)
>
> end
>
>
> bootstrap "difatt" difren=r(difren), reps(100)
>
>
> Best wishes,
>
> Fabio
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