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Re: st: how to generate parent variables matched to their children in household level data set?
From
Nick Cox <[email protected]>
To
[email protected]
Subject
Re: st: how to generate parent variables matched to their children in household level data set?
Date
Sun, 24 Feb 2013 15:01:07 +0000
As a small correction here that does not affect the major points:
Haena said "indicator variable" and I echoed her, but we both meant
"identifier variable".
Nick
On Sat, Feb 23, 2013 at 9:33 AM, Nick Cox <[email protected]> wrote:
> Haena:
>
> I am at a loss to understand what you are asking. My previous posts
> showed that with your sample data the code I used does work. It
> remains a mystery why you first reported otherwise, and also why you
> imply that the problem you stated is still unsolved. I just did that
> for you. It seems that you have not studied my code and its results.
>
> The absence of a single clear indicator variable is immaterial here.
> You want to copy data from mothers' and fathers' observations to
> children's; for that being able to link mother and father identifiers
> to children is necessary and sufficient, and done separately.
>
> My mention of -merge- just hints at a different method, but I have
> given a method that works. I was not stating or implying that you need
> to -merge-; that's merely a good alternative.
>
> If you want to know why my method works you need to study not only
> discussion of loops as in
>
> SJ-2-2 pr0005 . . . . . . Speaking Stata: How to face lists with fortitude
> . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . N. J. Cox
> Q2/02 SJ 2(2):202--222 (no commands)
> demonstrates the usefulness of for, foreach, forvalues, and
> local macros for interactive (non programming) tasks
>
> but also the use of -by:- as in
>
> SJ-2-1 pr0004 . . . . . . . . . . Speaking Stata: How to move step by: step
> . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . N. J. Cox
> Q1/02 SJ 2(1):86--102 (no commands)
> explains the use of the by varlist : construct to tackle
> a variety of problems with group structure, ranging from
> simple calculations for each of several groups to more
>
> My code requires the fact that under the aegis of -by:- subscripts
> (42 in -foo[42]- is a subscript) are numbered within groups, so the
> subscript [1] refers to the first observation in each group.
>
> As said, I don't see that you need any further code, so I have not
> studied your code beyond noticing that -forevar- is not a Stata
> command.
>
> Nick
>
> On Sat, Feb 23, 2013 at 8:36 AM, Haena Lee <[email protected]> wrote:
>> Nick,
>>
>> I would love to merge father's and mother's data with children. That
>> was my first choice.
>> As you may have noticed, however, my data doesn't have one clear
>> indicator variable of who is mother/father/child/grandparent. Although
>> there are ID_F and ID_M, what makes me confused is, ID_F and ID_M are
>> on the same row of children. I see "fid and mid" from your previous
>> answer is also located on children's row. So how do I tell stata to
>> generate a new indicator of "mothers" and to treat it as a property of
>> mothers, not children? So that eventually I would extract moms from
>> this raw data (e.g., keep ID BMI_M EMP_M if mom==1) and merge (1:many)
>> it based on key variable (ID_fam) with children's data?
>>
>> Assuming looping would do this work,
>>
>> gen mom=.
>> unab Y: ID
>> unab Z: ID_M
>> forevar x of newlist mom
>> replace `x' ==1 if Y==Z
>> }
>>
>> Please note that I am not familiar with the concept of looping. Just
>> taught myself today for a little bit so I am not sure if those
>> commands above would make sense. If not, let me know. I'd happy to
>> explain it again.
>>
>> Haena
>>
>> On Fri, Feb 22, 2013 at 7:54 PM, Nick Cox <[email protected]> wrote:
>>> Note that I wrote that FAQ some years ago. Now I think why didn't I
>>> approach that as a -merge- problem? Create a dataset with fathers'
>>> data, one with mothers' data, and -merge- using those. There is still
>>> some fiddling around. This all goes with the simple idea that we have
>>> favourite tools.
>>>
>>> Nick
>>>
>>> On Sat, Feb 23, 2013 at 1:50 AM, Nick Cox <[email protected]> wrote:
>>>> That's an allusion is to my FAQ
>>>>
>>>> FAQ . . Creating variables recording prop. of the other members of a group
>>>> . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . N. J. Cox
>>>> 4/05 How do I create variables summarizing for each
>>>> individual properties of the other members of a
>>>> group?
>>>>
>>>> http://www.stata.com/support/faqs/data-management/creating-variables-recording-properties/
>>>>
>>>> I don't know why you report problems. The code suggested there works
>>>> as intended. Here it is again run on your example data:
>>>>
>>>> . by ID_fam (ID), sort: gen pid = _n
>>>>
>>>> . gen byte fid = .
>>>> (7 missing values generated)
>>>>
>>>> . gen byte mid = .
>>>> (7 missing values generated)
>>>>
>>>> . summarize pid, meanonly
>>>>
>>>> . forval i = 1 / `r(max)' {
>>>> 2. by ID_fam: replace fid = `i' if ID_F == ID[`i'] &
>>>> !missing(ID_F)
>>>> 3. by ID_fam: replace mid = `i' if ID_M == ID[`i'] &
>>>> !missing(ID_M)
>>>> 4. }
>>>> (3 real changes made)
>>>> (0 real changes made)
>>>> (0 real changes made)
>>>> (3 real changes made)
>>>> (0 real changes made)
>>>> (0 real changes made)
>>>> (0 real changes made)
>>>> (0 real changes made)
>>>>
>>>> . l
>>>>
>>>> +----------------------------------------------------------------------------------+
>>>> | ID_F ID_M BMI ID ID_fam Emp
>>>> pid fid mid |
>>>> |----------------------------------------------------------------------------------|
>>>> 1. | 26.501 A901963701 A9019637 1
>>>> 1 . . |
>>>> 2. | 20.483 A901963702 A9019637 1
>>>> 2 . . |
>>>> 3. | A901963701 A901963702 20.924 A901963703 A9019637 .
>>>> 3 1 2 |
>>>> 4. | 27.209 A901963801 A9019638 1
>>>> 1 . . |
>>>> 5. | 31.733 A901963802 A9019638 .
>>>> 2 . . |
>>>> |----------------------------------------------------------------------------------|
>>>> 6. | A901963801 A901963802 18.018 A901963803 A9019638 .
>>>> 3 1 2 |
>>>> 7. | A901963801 A901963802 19.054 A901963804 A9019638 .
>>>> 4 1 2 |
>>>> +----------------------------------------------------------------------------------+
>>>>
>>>> Using the same logic, we copy parents' employment and mothers' BMI as desired:
>>>>
>>>> . gen BMI_M = .
>>>> (7 missing values generated)
>>>>
>>>> . gen Emp_M = .
>>>> (7 missing values generated)
>>>>
>>>> . gen Emp_F = .
>>>> (7 missing values generated)
>>>>
>>>> . summarize pid, meanonly
>>>>
>>>> . forval i = 1 / `r(max)' {
>>>> 2. by ID_fam: replace BMI_M = BMI[`i'] if ID_M == ID[`i'] & !missing(ID_M)
>>>> 3. by ID_fam: replace Emp_M = Emp[`i'] if ID_M == ID[`i'] & !missing(ID_M)
>>>> 4. by ID_fam: replace Emp_F = Emp[`i'] if ID_F == ID[`i'] & !missing(ID_F)
>>>> 5. }
>>>> (0 real changes made)
>>>> (0 real changes made)
>>>> (3 real changes made)
>>>> (3 real changes made)
>>>> (1 real change made)
>>>> (0 real changes made)
>>>> (0 real changes made)
>>>> (0 real changes made)
>>>> (0 real changes made)
>>>> (0 real changes made)
>>>> (0 real changes made)
>>>> (0 real changes made)
>>>>
>>>>
>>>> Here are the results:
>>>>
>>>> . l
>>>>
>>>> +-----------------------------------------------------------------------------------------------+
>>>> | ID_F ID_M BMI ID ID_fam Emp
>>>> pid BMI_M Emp_M Emp_F |
>>>> |-----------------------------------------------------------------------------------------------|
>>>> 1. | 26.501 A901963701 A9019637 1
>>>> 1 . . . |
>>>> 2. | 20.483 A901963702 A9019637 1
>>>> 2 . . . |
>>>> 3. | A901963701 A901963702 20.924 A901963703 A9019637 .
>>>> 3 20.483 1 1 |
>>>> 4. | 27.209 A901963801 A9019638 1
>>>> 1 . . . |
>>>> 5. | 31.733 A901963802 A9019638 .
>>>> 2 . . . |
>>>> |-----------------------------------------------------------------------------------------------|
>>>> 6. | A901963801 A901963802 18.018 A901963803 A9019638 .
>>>> 3 31.733 . 1 |
>>>> 7. | A901963801 A901963802 19.054 A901963804 A9019638 .
>>>> 4 31.733 . 1 |
>>>> +-----------------------------------------------------------------------------------------------+
>>>>
>>>> Nick
>>>>
>>>> On Fri, Feb 22, 2013 at 10:45 PM, Haena Lee <[email protected]> wrote:
>>>>
>>>>> I am working on investigating the relationship between maternal
>>>>> employment status and prevalence of childhood obesity using a
>>>>> nationally representative data (KNHANES). Suppose I have ID(all
>>>>> observations including both children and parents), ID_fam (household
>>>>> indicator),
>>>>> ID_F( father's ID), ID_M (mother's ID), BMI (body mass index) and
>>>>> finally Emp (employment status 1 if employed; 0 if non-employed) as
>>>>> the following;
>>>>>
>>>>> ID_F ID_M BMI ID ID_fam Emp
>>>>> 26.501 A901963701 A9019637 1
>>>>> 20.483 A901963702 A9019637 1
>>>>> A901963701 A901963702 20.924 A901963703 A9019637 .
>>>>> 27.209 A901963801 A9019638 1
>>>>> 31.733 A901963802 A9019638 .
>>>>> A901963801 A901963802 18.018 A901963803 A9019638 .
>>>>> A901963801 A901963802 19.054 A901963804 A9019638 .
>>>>>
>>>>> And ultimately, I would like to have a data set like this following;
>>>>>
>>>>> ID (children) ID_fam BMI Mom's Bmi Mom's Emp Dad's Emp
>>>>> A901963703 A9019637 20.924 20.483 1 1
>>>>> A901963803 A9019638 18.018 31.733 . 1
>>>>> A901963804 A9019638 19.054 31.733 . 1
>>>>>
>>>>> Given this, my question is 1) how to map the properties of other
>>>>> family members to children within each household, using loop, or 2)
>>>>> how to generate an indicator of mother (1 if ID == ID_M; 0 otherwise)?
>>>>> I found Nick Cox's helpful example and imitated it as the following;
>>>>>
>>>>> by ID_fam (ID), sort: gen pid = _n
>>>>> gen byte fid = .
>>>>> gen byte mid = .
>>>>> summarize pid, meanonly
>>>>> forval i = 1 / `r(max)' {
>>>>> by ID_fam: replace fid = `i'
>>>>> if ID_F == ID[`i'] & !missing(ID_F)
>>>>> by ID_fam: replace mid = `i'
>>>>> if ID_M == ID[`i'] & !missing(ID_M)
>>>>> }
>>>>>
>>>>> And it didn't produce any meaningful values but missing. Please
>>>>> advise. Thank you so much for any help in advance.
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