The first error is a Statalist
mistake: you appear to be using Stata 8 and not
telling us that.
More seriously, in your program [not "do file"]
program kuznets, rclass
args lnSEC lnGDPC lnGDPC2
tsset countrycode year
xtabond2 lnSEC l1.lnSEC lnGDPC lnGDPC2, gmm(l1.lnSEC) ///
iv(lnGDPC lnGDPC2)
gen kuz = exp(-_coef[lnGDPC]/(2*_coef[lnGDPC2]))
return scalar x1 = kuz
end
You do nothing with the results of -args-, so that can go.
I doubt you need to -tsset- every time, but you'd need to
check that.
There is no need to put a constant in a variable. It's poor style.
So, this looks more like
program kuznets, rclass
tsset countrycode year
xtabond2 lnSEC l1.lnSEC lnGDPC lnGDPC2, gmm(l1.lnSEC) ///
iv(lnGDPC lnGDPC2)
return scalar x1 = exp(-_coef[lnGDPC]/(2*_coef[lnGDPC2]))
end
Now what -bootstrap- should pick up is r(x1):
So your call should be more like
bootstrap "kuznets" r(x1), reps(25) cluster(countrycode)
idcluster(countryrs)
Incidentally, I am no -bootstrap- expert but 25 seems awful low
to me.
Also, I don't see that you need an intermediate program
here at all. -bootstrap- could call -xtabond2- directly.
Nick
[email protected]
Carl Nelson
> I created the following do file to obtain bootstrapped
> confidence intervals.
>
> program kuznets, rclass
> args lnSEC lnGDPC lnGDPC2
> tsset countrycode year
> xtabond2 lnSEC l1.lnSEC lnGDPC lnGDPC2, gmm(l1.lnSEC)
> iv(lnGDPC lnGDPC2)
> gen kuz = exp(-_coef[lnGDPC]/(2*_coef[lnGDPC2]))
> return scalar x1 = kuz
> end
>
> bootstrap "kuznets" kuz, reps(25) cluster(countrycode)
> idcluster(countryrs)
>
> The result is:
>
> command: kuznets
> statistic: _bs_1 = kuz
>
> Bootstrap statistics Number of
> obs = 1980
> N of
> clusters = 66
>
> Replications = 25
>
> --------------------------------------------------------------
> ----------------
> Variable | Reps Observed Bias Std. Err. [95%
> Conf. Interval]
> -------------+------------------------------------------------
> ----------------
> _bs_1 | 0 42843.02 . .
> . . (N)
> |
> . . (P)
> |
> . . (BC)
> --------------------------------------------------------------
> ----------------
> Note: N = normal
> P = percentile
> BC = bias-corrected
>
> insufficient observations to compute bootstrap standard errors
> no results will be saved
> r(2000);
>
> It looks like I am only getting one replication of kuz.
>
> I would appreciate any help identifying my error.
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