Re: st: Program syntax for svy bootstrap or bs4rw

[Jeffrey Pitblado <jpitblado@stata.com>]

Mark McGovern<markemcgovern@gmail.com> asked a question about programming
syntax and using -svy bootstrap- or my -bs4rw- prefix command. Stas Kolenikov
and Steve Samuels replied with several good suggestions, but Mark is still
having some trouble:

> Thank you Steve and Stas for your suggestions. For now I can work with
> bs4rw, although at some point I think I might need to use some of the
> functionality of svy, so I may have to return to this in the future.
>
> As you pointed out Steve, from the Stata 12 programming manual (p.326):
>
> 1. Command must be eclass and allow iweights and accept the standard
> estimation syntax.
> 2. Command must save the model coefficients and ancillary parameters
> in e(b) and the estimation sample size in e(N), and it must identify
> the estimation subsample in e(sample);
> 3. svy’s vce(bootstrap), vce(brr), and vce(sdr) require that command
> have svyb as a property.
>
> I thought these were satisfied as the original code below does return
> results in e() in the usual way from "regress". For example,
> specifically overwriting e() does not help as in the below.

Here is Mark's code:

> capture program drop test1
> program define test1, eclass properties(svyb)
>         syntax [if] [in] [pw iw]
>         marksample touse
>         tempvar b V
>         qui xi:reg age race [`weight'`exp'] if `touse'
>         capture drop re1
>         predict re1
>         qui xi:reg birthwgt re1 [`weight'`exp'] if `touse'
>         local nobs = e(N)
>         matrix `b' = e(b)
>         matrix `V' = e(V)
>         ereturn post `b' `V', esample(`touse')
>         ereturn local cmd="test1"
>         ereturn scalar N = `nobs'
>         ereturn display
> end
>
> svy : test1

The problem here is that

	. svy : test1

looks like a replay call to -svy-.  Mark put all the model specfication
information in the -test1- program.  Mark can add something to the syntax
to -test1- that will prevent -svy- from trying to replay nonexistent results.
I would suggest

	. svy : test1 in 1/l

-- Jeff Pitblado
   jpitblado@stata.com

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