st: bootstrap

["Cowell, Alexander J." <cowell@rti.org>]

Hi there

 

I am using Stata version 8 and wish to bootstrap two ratios (ratio6 and ratio12).  The ratios are combinations of regression coefficients from two separate regressions.  When I type the bootstrap command

 

bootstrap "cer" ratio6 ratio12, r(1) trace

 

I get the response:

 

ratio6 not found

error in statistic: ratio6

r(111);

 

This is maddening, because I used to bootstrap all the time using older versions of Stata. 

 

Here is the "cer" program:

 

program cer, rclass

        version 8.0

        tempname y6 y12 c6 c12

        use "/projects/p6/07572.005/effectiveness/data/analysis1.dta", clear

        logit mj jt2 jt3 jbtc t2 t3 rapcourt nonwhite  gender age trsk, or nolog cluster(id)

        scalar `y6' = _b[jt2]*100

        scalar `y12' = _b[jt3]*100

        use "/projects/p6/07572.005/cost/data/cost_analysis.dta", clear

        xtreg jt0 jt2 jt3 jbtc t0 t2 t3 nonwhite gender age rapcourt trsk, re i(id)

        scalar `c6' = _b[jt2]

        scalar `c12' = _b[jt3]

        return scalar ratio6 = `c6'/`y6'

        return scalar ratio12 = `c12'/`y12'

end  

 

I think it's something simple, but I just don't get it!  The trace option in bootstrap doesn't seem to help here.

 

Thanks in advance

 

Alex Cowell