# Re: st: Decomposition of outcome differentials by module JMPIERCE2

 From Michael Buryak To statalist@hsphsun2.harvard.edu Subject Re: st: Decomposition of outcome differentials by module JMPIERCE2 Date Mon, 20 Jul 2009 14:45:39 +0300

```Thank you very much

On Mon, Jul 20, 2009 at 1:35 PM, Ben Jann<ben.jann@gmail.com> wrote:
> Let y(G) denote the mean outcome for group G. The decomposition of the
> difference in differences
>
> D = [y(isr_nat) - y(isr_imm)] - [y(ger_nat) - y(ger_imm)]
>
> is then computed as
>
>  . jmpierce2 ger_nat ger_imm isr_nat isr_imm
>
> Germany is the benchmark. If you want Israel be the benchmark, type
>
>  . jmpierce2 ger_nat ger_imm isr_nat isr_imm, benchmark(2)
>
> The choice of the benchmark does not change the overall differential.
> However, it changes how the differential is decomposed. See the
> formulas in -help jmpierce2-.
>
> ben
>
>
> On Mon, Jul 20, 2009 at 10:59 AM, Michael
> Buryak<michael.buryak@gmail.com> wrote:
>> Hello, Statalist
>>
>> Something not clear for me in the results after using the module JMPIERCE2.
>>
>> For example:
>> I have the estimated wage for four groups : two in Israel and two in Germany.
>> In each country one group is natives and second group is immigrants.
>> So four groups:
>> 1) ISR_NAT
>> 2) ISR_IMM
>> 3) GER_NAT
>> 4) GER_IMM
>>
>> If I want to decompose difference in difference:
>>
>> D = [(D ISR_NAT - D ISR_IMM) - (D GER_NAT - D GER_IMM)]
>>
>> Is it my command right:
>>
>> reg wage hour age educ if isr_nat==1
>> est store isr_nat
>> reg wage hour age educ if isr_imm==1
>> est store isr_imm
>> reg wage hour age educ if ger_nat==1
>> est store ger_nat
>> reg wage hour age educ if ger_imm==1
>> est store ger_imm
>> jmpierce2 isr_nat isr_imm ger_nat ger_imm, benchmark(1)
>>
>> Which order of estimators in command jmpierce2 is right for my decomposition?
>> If I change to the parameter benchmark(2), the total difference is same. Why?
>>
>> What is the role of parameters "benchmark" and "reference" in my order
>> of estimators:  isr_nat isr_imm ger_nat ger_imm?
>>
>> Michael
>>
>> *
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>>
>
> *
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>

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```