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Re: st: Creating a loop for bsample


From   Austin Nichols <austinnichols@gmail.com>
To   statalist@hsphsun2.harvard.edu
Subject   Re: st: Creating a loop for bsample
Date   Sat, 25 Jul 2009 23:47:42 -0400

Farasat Bokhari<farasat.bokhari@yahoo.com> :
No--don't use the weight option in -bsample-.  If you want to do it
the quick-n-dirty way, save the relevant subset of data, -use- and
resample with -bsample- (unweighted resample) then do weighted
estimation on each draw using the original sample weights (the N
totals will be wrong in each resample, but this is likely not a big
deal, depending on what you want)--or ask Stas Kolenikov (see also
http://ideas.repec.org/p/boc/nsug08/19.html or find him in DC this
week or next) about the right way (if you resample you are supposed to
redo all the weights and poststratification etc. for each draw).

On Sat, Jul 25, 2009 at 4:22 PM, Farasat
Bokhari<farasat.bokhari@yahoo.com> wrote:
> I think I have the looping and posting commands figured out and the results looks fine.  However, I am now worried per your comment: I understand that bsample changes the values of the weight variable to be 0,1,2, etc. to indicate how many times this obs. is chosen in the sample BUT i thought it was doing the selection based on the original values of the weights.  If this is not so the clearly my code is not doing what I thought it was (else its ok).  My code is given below (your thoughts would be appreciated).
>
> fb
>
> ------code below --------
>
>
> set memory 99999k
> set matsize 400
> #delimit ;
> cd I:\bokhari\fb_research\analysis\adhd\schoollaws\schoollaws_data;
> use nschschlaws2003;
>
> #delimit;
> svyset idnumr [pw=weight], strata(state);
> gen myflag1 = 0;
> replace myflag1 = 1 if sample1 == 1 & pubsch == 1;
> gen wt2 = weight;
>
>
> #delimit;
> postfile mysim assistance rewards sanctions using simres2, replace ;
>
>  forvalues i = 1/100 {
>  bsample 6700 if myflag1 == 1, weight(wt2)
>  quietly: probit adhd assistance rewards sanctions gender age black othrace hispanic family2 family3 family4 poverty1-poverty7 edu1 edu2 conachive1 conachive2 schcalls1 schcalls2 if wt2!=0  [fw=wt2]
>  replace wt2 = weight
>  local b1 = _b[assistance]
>  local b2 = _b[rewards]
>  local b3 = _b[sanctions]
>  post mysim (`b1') (`b2') (`b3')
>  display "Run Done:" `i'
>  }
> postclose mysim
>
> #delimit;
> clear all;
> #delimit;
> use simres2;
>
> mean assistance rewards sanctions;
> mean assistance rewards sanctions, level(90);
>

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