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Re: st: sampling using matching variables


From   Steve Samuels <sjsamuels@gmail.com>
To   statalist@hsphsun2.harvard.edu
Subject   Re: st: sampling using matching variables
Date   Tue, 17 Aug 2010 23:01:43 -0400

I understand: When reviewers say "hop", I, with few exceptions, hop
too. I don't think this would be one of those exceptions.

Best wishes.

Steve

On Tue, Aug 17, 2010 at 6:43 PM, Debs Majumdar <debs_stata@yahoo.com> wrote:
> @Steve: I don't. But 2 of the reviewers wanted it as a part of sensitivity
> analyses. Thanks anyways.
>
> -Debs
>
>
>
>
> ----- Original Message ----
> From: Steve Samuels <sjsamuels@gmail.com>
> To: statalist@hsphsun2.harvard.edu
> Sent: Tue, August 17, 2010 9:52:46 AM
> Subject: Re: st: sampling using matching variables
>
> Why do you require 1-1 matching?  There is more information (= greater
> power, smaller standard errors) in analyses of matched sets with >1
> person from each group.
>
> If you insist, despite this advice, then let  "mset" be the variable
> that identifies a matched set -will differ from command-to-command (I
> like -cem- myself):
>
> **********************************************
> set seed 12345  // choose your own seed
> gen u=uniform()
> bysort mset race (u): keep if _n==1
> *********************************************
>
> Steve
>
> --
> Steven Samuels
> sjsamuels@gmail.com
> 18 Cantine's Island
> Saugerties NY 12477
> USA
> Voice: 845-246-0774
> Fax:    206-202-4783
>
>
>
> On Tue, Aug 17, 2010 at 12:29 PM, Christopher Swearingen
> <christopher.swearingen@gmail.com> wrote:
>> Debs,
>>
>> I have used the contributed psmatch2, a propensity scoring method, to
>> match groups on various covariates.
>>
>> findit psmatch2
>>
>> *** 1-1 age only matching
>> psmatch2 nonwhite age, noreplacement
>> gen age_matched = _weight
>>
>> *** 1-1 age & education matching
>> psmatch2 nonwhite age education, noreplacement
>> gen age_education_matched = _weight
>>
>> *** 1-1 age & education & gender matching
>> psmatch2 nonwhite age education gender, noreplacement
>> gen age_education_gender_matched = _weight
>>
>> ~c
>> ________________________________________________________
>> Christopher Swearingen, Ph.D.
>> Assistant Professor of Pediatrics and Biostatistics
>> University of Arkansas for Medical Sciences
>> Department of Pedatrics
>> One Children's Way, Slot 512-43
>> Little Rock, AR 72202
>>
>> http://www.arpediatrics.org/research/biostatistics
>>
>>
>>
>> On Mon, Aug 16, 2010 at 10:27 PM, Debs Majumdar <debs_stata@yahoo.com> wrote:
>>> Hi,
>>>
>>>  I have a dataset of around 1000 people where 750 are whites and 250 are
>>> non-whites. I have variables for age (35-75), education (0-20) and gender (0
>>or
>>> 1). Also in the dataset I have item responses to 10 questions for each of
>>these
>>> 1000 people.
>>>
>>>  I would like to create dataset(s) where one white is matched with a
> non-white
>>> person in terms of age only, age and education, and age,education and gender.
>>>
>>> Initially, I tried matching on age only. But then for some cases I end up with
>>>3
>>>
>>> whites and 1 non-white for the same age category. At that time I would like
> to
>>> drop any 2 of those 2 at random in the new dataset so that the matching is
>>> always 1-1. How do I do that?
>>>
>>> I have tried using cem, vmatch etc. but didn't get what I want.
>>>
>>> Thanks,
>>>
>>> -Debs
>>>
>>>
>>>
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-- 
Steven Samuels
sjsamuels@gmail.com
18 Cantine's Island
Saugerties NY 12477
USA
Voice: 845-246-0774
Fax:    206-202-4783

*
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*   http://www.stata.com/help.cgi?search
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*   http://www.ats.ucla.edu/stat/stata/


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