Re: st: To: Statalist <statalist@hsphsun2.harvard.edu>

["Dimitriy V. Masterov" <dvmaster@gmail.com>]

Fernando,

I overlooked the paper thinking it was irrelevant since the probit
option was added later. Quite the opposite. Makes much more sense.
Thanks!

DVM

On Tue, Nov 13, 2012 at 6:02 PM, Fernando Rios Avila <f.rios.a@gmail.com> wrote:
> The problem is that you are not using any of the right options in the
> -oaxaca- command. For instance, what you are referring to is a two
> fold decomposition, whereas by default Oaxaca does a three fold
> decomposition (for more detail look at the paper and documentation).
> For instance, if you do :
> oaxaca y x, by(d) probit nodetail  weight(0)
> you will have the results in the more traditional two fold way.
> (again, look at the documentation)
> HTH
> Fernando
>
> On Tue, Nov 13, 2012 at 8:55 PM, Dimitriy V. Masterov
> <dvmaster@gmail.com> wrote:
>> I am trying to make sense of the results of a Oxaca-Blinder
>> decomposition produced by Ben Jann's oaxaca command (version 4.0.5
>> from ssc). I have a binary outcome y, a single continuous explanatory
>> variable x (0-100), and a binary group indicator d:
>>
>> oaxaca y x, by(d) probit nodetail
>>
>> Blinder-Oaxaca decomposition                      Number of obs   =    2178524
>>                                                   Model           =     probit
>> Group 1: DElectronics_1 = 0                       N of obs 1      =    1612480
>> Group 2: DElectronics_1 = 1                       N of obs 2      =     566044
>>
>> ------------------------------------------------------------------------------
>>    bbe_flag1 |      Coef.   Std. Err.      z    P>|z|     [95% Conf. Interval]
>> -------------+----------------------------------------------------------------
>> overall      |
>>      group_1 |   .0617275   .0001892   326.25   0.000     .0613567    .0620983
>>      group_2 |   .0698966   .0003379   206.85   0.000     .0692343    .0705589
>>   difference |  -.0081692   .0003873   -21.09   0.000    -.0089282   -.0074101
>>   endowments |  -.0135059   .0001323  -102.10   0.000    -.0137651   -.0132466
>> coefficients |   .0024407   .0004099     5.95   0.000     .0016374     .003244
>>  interaction |    .002896   .0001549    18.69   0.000     .0025924    .0031996
>> ------------------------------------------------------------------------------
>>
>> The rate for Group 2 is about 0.8 of a percent point higher. That can
>> be broken out as the sum:
>> (1) the difference due to different characteristics x (-1.35)
>> (2) the difference in the effect of x on y (+0.24)
>> (3) interaction (+0.3)
>>
>> In the draft version of Yun's 2004 paper (link below), I only see two
>> terms that correspond to (1) and (2) above in the probit example. The
>> interaction seems to be a sort of residual. Where does it come from?
>>
>> Finally, using the SJ version of Yun's mvdcmp command, also produces
>> only two terms. His difference due to coefficients seems to be the sum
>> of (2) and (3) from above.
>>
>> DVM
>>
>> http://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=2&ved=0CDUQFjAB&url=http%3A%2F%2Fftp.iza.org%2Fdp877.pdf&ei=roWiUIjUB-TXigKfk4GYCg&usg=AFQjCNF6vZ3LumWLgT3tZE65rgxqSyoUSg&sig2=XNMCW_y-Cp_ZjdmNZnX64g&cad=rja
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