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# Re: st: RE: generating variable from combination of three categorical variable

 From Maria Fleischmann To statalist@hsphsun2.harvard.edu Subject Re: st: RE: generating variable from combination of three categorical variable Date Wed, 18 May 2011 15:17:09 +0200

```Shouldn't it be:

gen var4 = max(var1, var2, var3)
replace var4 = 3 if (var1 + var2 + var3) == 3 & var4!=1

otherwise you subsitute var4=3 if var1, var2, and var3 are all equal to '1'

Maria

On 18 May 2011 14:37, Nick Cox <n.j.cox@durham.ac.uk> wrote:
>
> You have six rules, which I think can be collapsed to 4 in the first instance.
>
> (a) var1==0 & var2==0 & var3==0,
> (b) var4=1 if var1==1 & var2==1 & var3==1
> (c) var4=2 if var1==2 & var2==2 & var3==2
> (d) var4=1 if var1|var2|var3 is having 0 and 1 only
> (e) var4=2 if var1|var2|var3 is having 0 and 2 only
> (f) var4 is 3 if var1|var2|var3 is 0,1 and 2
>
> gen var4 = 0 if max(var1, var2, var3) == 0            (a)
> replace var4 = 1 if max(var1, var2, var3) == 1        (b), (d)
> replace var4 = 2 if max(var1, var2, var3) == 2        (c), (e)
> replace var3 = 3 if (var1 + var1 + var2) == 3         (f)
>
> Now it is evident that you can simplify
>
> gen var4 = max(var1, var2, var3)
> replace var3 = 3 if (var1 + var1 + var2) == 3
>
> Nick
> n.j.cox@durham.ac.uk
>
> prakash singh
>
> In my survey data, I have three categorical variable with 0, 1 and 2 as
> three category.
> Now I want to make a variable using combination of these three
> variables.
>
> The combination is such that generated variable var4 == 0 if
> var1==0 & var2==0 & var3==0,
> var4=1 if var1==1 & var2==1 & var3==1,
> var4=2 if var1==2 & var2==2 & var3==2,
> var4=1 if var1|var2|var3 is having 0 and 1 only
> var4=2 if var1|var2|var3 is having 0 and 2 only
> var4 is 3 if var1|var2|var3 is 0,1 and 2
>
> for exmple (see below)
>
> var1 var2 var3 var4
> 0     0     0      0
> 1    1     1       1
> 2    2      2      2
> 0    1     2       3
> 0    1      1      1
> 1    2      0      3
>
> I am using stata10.
>
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```