The second part of the table actually shows that the Hessian-based
standard errors of logit are biased down by some 10-20%, for whatever
reason. The average standard error for indlninc variable is 0.375,
while the bootstrap measure of variability is 0.483. The first one is
purely model-based, while the second one is more robust to various
model misspecifications. I'd be curious as to whether -logit ...,
robust- standard errors would be close to the bootstrap ones, in your
case.
On 12/8/08, Maarten buis <[email protected]> wrote:
> --- "Supnithadnaporn, Anupit" <[email protected]> wrote:
> > I am using bootstrap in my study and Stata reports 2 types of
> > standard errors of beta: (1) bootstrap std. err. right to the
> > observed coef. and (2) se shown in the second part of the table.
> > They are quite different.
>
> <snip>
>
> > . local vehicle age lnodo peuro pasia pother
> > . local owner black other
> > . set seed 9999
> > . bootstrap _b _se, reps(10000) saving("C:\data\logitBOOT2Abse.dta",
> > replace): ///
> > logit tresimp indlninc `owner' `vehicle', robust
>
>
> The standard error in the second part is the standard error of the
> standard error. Remember that the standard error is also an estimate,
> so you can have sampling uncertainty around that too. The standard
> error in the second part of your table tells you about the uncertainty
> about the estimate of the standard error. So, it can be interesting too
> look at it, but the standard error you are after is in the first part
> of the table. Normally you would not ask for the second part of your
> table (and exclude the -_se- from the -bootstrap- statement).
>
> Hope this helps,
> Maarten
>
> -----------------------------------------
> Maarten L. Buis
> Department of Social Research Methodology
> Vrije Universiteit Amsterdam
> Boelelaan 1081
> 1081 HV Amsterdam
> The Netherlands
>
> visiting address:
> Buitenveldertselaan 3 (Metropolitan), room N515
>
> +31 20 5986715
>
> http://home.fsw.vu.nl/m.buis/
> -----------------------------------------
>
>
>
>
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>
--
Stas Kolenikov, also found at http://stas.kolenikov.name
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