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Re: st: Matching


From   Sophie Jensen <thorns.n.roses@gmail.com>
To   statalist@hsphsun2.harvard.edu
Subject   Re: st: Matching
Date   Mon, 4 Oct 2010 23:50:26 +0100

Here's what I've done... how would you interpret that:

. psmatch2 treatment white fsm male if year>2006, n(1)

Probit regression                                 Number of obs   =      15471
                                                  LR chi2(4)      =     322.40
                                                  Prob > chi2     =     0.0000
Log likelihood = -678.85535                       Pseudo R2       =     0.1919

------------------------------------------------------------------------------
   treatment |      Coef.   Std. Err.      z    P>|z|     [95% Conf. Interval]
-------------+----------------------------------------------------------------
   ewhite |    .172414   .1514341     1.14   0.255    -.1243915    .4692194
         fsm |   1.650061   .2705032     6.10   0.000     1.119885    2.180238
male |   .0000787   .0000105     7.50   0.000     .0000581    .0000992
       _cons |   .4350676   .8062152     0.54   0.589    -1.145085     2.01522
------------------------------------------------------------------------------


pstest fsm eth_white ks2mn outwage_male

----------------------------------------------------------------------------
                        |       Mean               %reduct |     t-test
    Variable     Sample | Treated Control    %bias  |bias| |    t    p>|t|
------------------------+----------------------------------+----------------
         fsm  Unmatched | .32883   .13543    136.0         |  18.34  0.000
                Matched | .32883     .328      0.6    99.6 |   0.04  0.968
                        |                                  |
white  Unmatched | .58394     .829    -89.1         | -12.70  0.000
                Matched | .58394   .54751     13.2    85.1 |   1.00  0.318
                        |                                  |
 male  Unmatched |  28221    24729     92.7         |  11.82  0.000
                Matched |  28221    28606    -10.2    89.0 |  -0.87  0.387
                        |                                  |



On Mon, Oct 4, 2010 at 11:35 PM, Santosh Kumar <santosh.uh@gmail.com> wrote:
> This is an example of matching with 3 neighbors.
>
> psmatch2 improved, pscore(pscore) outcome(diarr) common caliper(.001)
> neighbor(3)
> There are observations with identical propensity score values.
> The sort order of the data could affect your results.
> Make sure that the sort order is random before calling psmatch2.
> (4005 missing values generated)
>
> Variable     Sample     Treated     Controls   Difference         S.E.   T-stat
>
> diarr  Unmatched  .104890901   .125810627  -.020919727   .001373497   -15.23
> ATT  .104893374   .110885821  -.005992448   .007151216    -0.84
>
> Note: S.E. for ATT does not take into account that the propensity
> score is estimated.
>
> psmatch2:    psmatch2: Common
> Treatment         support
> assignment  Off suppo  On suppor      Total
>
> Untreated          0    159,136    159,136
> Treated          2     84,829     84,831
>
> Total          2    243,965    243,967
>
> On Mon, Oct 4, 2010 at 6:28 PM, Sophie Jensen <thorns.n.roses@gmail.com> wrote:
>> Could someone perhaps explain the process of this kind of matching please.
>>
>> Thanks
>>
>> S
>>
>> On Mon, Oct 4, 2010 at 11:26 PM, Sophie Jensen <thorns.n.roses@gmail.com> wrote:
>>> Dear statlisters,
>>>
>>> What is the difference between a 1-1 to match and the nearest
>>> neighbour match in stata. I would like to do a nearest neighbour
>>> match, a 1-1 and then specifiy a distance to match on.
>>>
>>> Thanks
>>>
>>> S
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>>
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>
>
>
> --
>
> Santosh
>
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