Re: st: foreach program

[Scott Cunningham <scunning@gmail.com>]

Nick,

I'm going to work with your program and see if I can learn something  
about my problem.

The "not working" - I'm getting 0's for incarceration rates and  
incarceration levels for all the cells.  There are people who are  
incarcerated in the data (that is, there are person weights for  
people with group quarter values equalling 200, meaning living in a  
correctional facility), meeting the criteria I specify as far as I  
can tell.

I will try your syntax, though.  Between the two of them (my code and  
yours), I hope I can see where the logic in my code is breaking down.

thanks,

scott

On Sep 8, 2006, at 11:16 AM, n j cox wrote:


> The report "not working" really is not at all transparent. From  
> your posting, I infer anything from "Stata complained" through  
> "results are all missing" to "results look implausible".
>
> This code would be better as a
>
> forval i = 1/`r(max)' {
>
> loop. I can't see a bug, but creating variables to hold constants
> and then -drop-ping them is not at all necessary.
>
> Here's a second try:
>
> egen group=group(fip race sex)
> su group, meanonly
>
> tempname itot ptot
> forval i = 1/`r(max)' {
> 	su perwt if inrange(age,15,19) & group==`i' & gqtyped==200, ///   
> 		 meanonly
> 	scalar `itot' = r(sum) 	
> 	su perwt if inrange(age,15,19) & group==`i', meanonly
> 	scalar `ptot' = r(sum)
> 	replace ir_level = `itot' if age==15 & group==`i'
> 	replace pop_level = `ptot' if age==15 & group==`i'		
> 	replace ir = `itot'/`ptot' if age==15 & group==`i'
> }
>
> This assumes that your variables being -replace-d exist before
> the loop is entered. This probably misses your question, which may  
> hinge
> on the substantive logic, but you might pick up some Stata tips  
> anyway.
>
> Nick
> n.j.cox@durham.ac.uk
>
> Scott Cunningham
>
> I wrote a foreach loop to calculate incarceration rates that were
> specific to race-age-sex-state for 1980, but it appears not to have
> worked.  I'm unable to see why this is not working.  Can anyone shed
> some light on why this program would not have calculated
> incarceration rates?  The dataset is the 1980 US Census (longform
> survey, aka "5% sample").  The data is observations on persons, but
> uses a sampling method that requires summing up the person weights
> ("perwt") to find an estimate of the population of interest.
> Individuals were asked about housing units, and a person was
> classified as living in a "group quarter" if they lived in a dwelling
> unit that had at least 5 unrelated persons under the same roof.
> Surveys also report the kind of group quarter.  In 1980, information
> in the variable "gqtyped" told whether the person lived in a
> correctional facility - gqtyped=200 means the person lives in a
> correctional facility.  I attempted to create, in the following loop,
> an incarceration rate for the 15-19 year old age cohort, according to
> the demographics noted in the grouping fip (Census variable
> indicating the United States state), race (black and white only in
> this sample) and sex.
>
>
>
> egen group=group(fip race sex)
> su group, meanonly
>
> foreach i of num 1/`r(max)' {
> 		gen i=perwt if age>=15 & age<=19 & group==`i' & gqtyped==200
> 		gen p=perwt if age>=15 & age<=19 & group==`i'
> 		egen itot=sum(i)
> 		egen ptot=sum(p)
> 		replace ir_level=itot if age==15 & group==`i'
> 		replace pop_level=ptot if age==15 & group==`i'		
> 		replace ir=itot/ptot if age==15 & group==`i'
> 		drop i p itot ptot
> 		}
>
>
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