Not sure this counts as "elegant", but if all your multiple case
variables follow the pattern f*m*, then the following program should do
it for you. Be sure to modify the list of stubs to be complete:
*****************begin multcase.ado
prog define multcase
version 7
foreach stub in f4 f6 f8 { /* <==== ADD LIST OF STUBS */
vl `stub'*
local varlist `r(varlist)'
local nstub : word count `varlist'
forval i=1/`nstub' {
gen `stub'_val_`i' = .
forval v=1/`nstub' {
qui replace `stub'_val_`i' = 0 if
`stub'm`v'!=. & `stub'_val_`i'==.
qui replace `stub'_val_`i' = 1 if
`stub'm`v'==`i'
}
}
}
end
prog define vl, rclass
syntax varlist
return local varlist `varlist'
end
***************end multcase.ado
> -----Original Message-----
> From: Lee Sieswerda [mailto:[email protected]]
> Sent: Friday, July 12, 2002 12:35 PM
> To: Statalist (E-mail)
> Subject: st: multiple response to binary
>
>
> Hello all:
> I have a data management problem (WinNT4, Stata v7).
>
> I have data from a questionnaire where some of the questions allow the
> respondent to choose multiple responses. Lets say there 7
> possible responses
> and they could choose any number of them. I would code this
> as a set of 7
> binary variables. Unfortunately, the way it was coded was not so
> straightforward. It was coded across 7 variables, but the
> responses were
> simply entered in the order in which they were given by the
> respondent. So
> the data look like this:
>
> f4m1 f4m2 f4m3 f4m4 f4m5 f4m6 f4m7
> 1 7 4 . . . .
> 1 . . . . . .
> 1 . . . . . .
> 1 . . . . . .
> 7 3 . . . . .
> 1 . . . . . .
> 1 2 3 4 . . .
> 1 2 3 4 6 . .
> 1 2 7 . . . .
> 1 . . . . . .
>
> As you can see, you cannot simply tabulate the number of people who
> responded 1, 2 , 3 etc because the responses are scattered over the 7
> variables in a different order for every person. The folks
> who provided me
> with this data use SPSS and they get around this problem by
> using "multiple
> responses sets". In SPSS, you can define a set of variables
> as a multiple
> response set (in this case, seven variables) and then ask for
> tables of
> frequencies and crosstabs generated from across the 7
> variables. It works,
> but I'd much rather use Stata than SPSS. Also, the SPSS
> solution is limited
> to simple tables and doesn't permit you to get chi-square or other
> statistics.
>
> Now, in Stata I know I can generate dummy variables from this
> mess like
> this:
> gen dum1 = 0
> replace dum1 = 1 if f4m1==1 | f4m2==1 | f4m3==1 etc.
> replace dum1 = . if f4m1==. & f4m2==. & f4m3==. etc.
> gen dum2 = 0
> etc.
>
> However, this is tedious in the extreme and there are many of
> these multiple
> response questions in the dataset. I could automate the
> procedure somewhat
> using -foreach-, but its still more brute force than
> elegance. Someone told
> me about a SAS solution to this problem using an array procedure. Does
> anyone have a nice elegant Stata solution to this problem?
>
> Thanks,
>
> Lee
>
> Lee Sieswerda, Epidemiologist
> Thunder Bay District Health Unit
> 999 Balmoral Street
> Thunder Bay, Ontario
> Canada P7B 6E7
> Tel: +1 (807) 625-5957
> Fax: +1 (807) 623-2369
> [email protected]
> www.tbdhu.com
>
> *
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>
*
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