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Re: st: Creating values for ID variables


From   "Sergiy Radyakin" <serjradyakin@gmail.com>
To   statalist@hsphsun2.harvard.edu
Subject   Re: st: Creating values for ID variables
Date   Thu, 16 Aug 2007 10:25:06 -0400

Hi,

the simpliest way (in both implementation and understanding) is to
1) create a file with two variables pers_id and educ
    here pers_id must be a unique identifier of a person and educ -
her education
    basically you almost have it, but your iid is not unique --
combine hhid and iid, say by gen pers_id=iid+hhid*100 (almost surely
you don't have more than 99 family members).

2) keep only pers_id and grade_completed, save the file

3) go back to the result of #1

4) replace fatherid to father_id=fatherid+100*hhid (and similar for mothers).

5) merge by this unique id with the file you saved in #2
    hint: you will have to temporarily rename variables on your way

Best regards, Sergiy



On 8/16/07, Austin Nichols <austinnichols@gmail.com> wrote:
> Prabal Kr. De--
> There is a trick using explicit subscripting, which requires you have
> no gap in individual IDs and that they correspond to observation
> numbers within household, as they do in your example. Then you can
> just:
>
> bys hhid (iid): g fathered=grade[fatherid]
> bys hhid (iid): g mothered=grade[motherid]
>
> If you have gaps in individual IDs, you have to use some trickery
> involving -fillin- to exploit the same trick.  Here is an example that
> tests for gaps and automates the trickery:
>
> clear
> input hhid  iid fatherid motherid grade
>      1001    1     .         .    6
>      1001    2     .         .    5
>      1001    3     1         2    3
>      1001    4     1         2    3
>      1002    1     .         .    5
>      1002    2     .         .    6
>      1002    3     1         2    8
>      1002    4     .         .    8
>      1002    5     3         4    1
>      1002    7     3         4    1
> end
> cap bys hhid (iid): assert iid==iid[_n-1]+1 if _n>1
> if _rc!=0 {
>  set obs `=_N+1'
>  su hhid, meanonly
>  loc fake=r(max)+1
>  replace hhid=`fake' in l
>  su iid, meanonly
>  expand `r(max)' in l
>  bys hhid: replace iid=_n if hhid==`fake'
>  fillin hhid iid
>  drop if hhid==`fake'
>  }
> bys hhid (iid): g fathered=grade[fatherid]
> bys hhid (iid): g mothered=grade[motherid]
> cap drop if  _fillin==1
> cap drop _fillin
> li, noo clean
>
>
> On 8/16/07, Prabal Kr. De <contactprabal@yahoo.com> wrote:
> > Hi!
> >   I have a household survey dataset which gives
> > householdid (hhid) individual id (iid) and
> > corresponding ids for father and mother. Therefore the
> > data looks like
> >
> > hhid    iid     fatherid        motherid        grade_completed
> > 1001    1       .       .       6
> > 1001    2       .       .       5
> > 1001    3       1       2       3
> > 1001    4       1       2       3
> > 1002    1       .       .       5
> > 1002    2       .       .       6
> > 1002    3       1       2       8
> > 1002    4       .       .       8
> > 1002    5       3       4       1
> >
> > I want to create two variables: fatheredu (father's
> > education) and motheredu (mother's education)
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