Great! Thank you.
Erasmo
On Thu, Dec 10, 2009 at 6:33 PM, Austin Nichols <[email protected]> wrote:
> Erasmo Giambona--
> Whether you want ATE or ATT depends on the substantive question you
> want the answer to. Imagine you have all the data, including
> (unobservable) counterfactual outcomes for each individual, and figure
> out what calculation you would want to make.
>
> Do you want to know:
>
> What is the effect of the last year of education (on earnings) for
> those who have 17 years of educ? (ATT)
>
> What would be the effect of the next year of education (on earnings)
> for those who have 16 years of educ, if we made them all get 17 years
> of educ? (ATC)
>
> Or the average of those two effects, using the pop weights of those
> with 16 and 17 years of educ? (ATE)
>
> If you think people are rationally deciding to pursue more educ when
> it gives a higher return, then ATT>ATC but that need not be the case
> in reality.
>
> On Thu, Dec 10, 2009 at 9:50 AM, Martin Weiss <[email protected]> wrote:
>> http://www.stata.com/meeting/dcconf09/dc09_nichols.pdf
>>
>> -----Ursprüngliche Nachricht-----
>> Betreff: st: Matching Estimator
>>
>> Dear All,
>>
>> I am trying to use the Abadie/Imbens (2002) estimator that one can
>> obtain with "nnmatch". Can somebody provide some intuition on the
>> difference between Average Treatment Effect (ATE) and Average
>> Treatment Effect on the Threated? In prticular, what does it mean that
>> in the case of the ATE "all observations are matched to their nearest
>> m neighbors of the opposite treatment group" (from help nnmatch)? Why
>> would one want to match the firms in the control group?
>>
>> Any suggestions/thoughts on the issue would be appreciated.
>>
>> Erasmo
>>
>>
>> References
>>
>> Abadie, A. and G. Imbens. 2002. Simple and Bias-Corrected Matching
>> Estimators. Tech. rep., Department of Economics, UC Berkeley.
>> http://emlab.berkeley.edu/users/imbens/.
>
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