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  • the `tebounds’ command - bound the average treatment effect

    Hi Statalists,

    I am reaching out with some questions regarding the `tebounds’ command. I am wondering how the command can distinguish whether the outcome variable is a positive or a negative outcome (e.g., NOobese or Obese), specifically, when Monotone Treatment Response (MTR) assumption is imposed.

    I am using a negative outcome (a dummy indicating if a household is food insecure or not) in my data, and the `tebounds’ output for the MTS+MTR assumptions give me a result [0.000, 0.137]. This is counterintuitive as my MTR assumption is that being in the food assistance program would not hurt the food insecurity status. In other words, it should be something like [a negative LB, 0.000].

    To illustrate this concern, I am using the dataset “MT-SBPdictionary.zip” on http://qed.econ.queensu.ca/jae/datasets/millimet001/ to replicate the authors’ results on p.428-429 (https://journals.sagepub.com/doi/pdf...867X1501500205).
    keep obese break1 ses
    gen NOTobese = 1 if obese == 0
    replace NOTobese = 0 if obese == 1
    tebounds NOTobese, treat(break1) erates(0) ncells(20) miv(ses) bs reps(100)
    1.png


    Following the authors, I use “NOTobese“ - a positive outcome and assume “negative selection” into the breakfast program. Although the values do not exactly match that presented in the paper, the general picture is consistent. Regarding the MTS+MTR assumptions, the Lower Bound is replaced by 0, implying the program participation will not hurt an individual’s “NOTobese” outcome.
    So far, I have no questions about the estimation.

    However, I am stuck when using a negative outcome (“Obese”). In the same story, the only thing changes are now I am measuring a “negative outcome” and assuming a “positive selection” into the program, i.e., those selected into the program are more likely to be obese.
    tebounds obese, treat(break1) erates(0) ncells(20) miv(ses) bs reps(100)
    I have a hard time interpreting the result of the MTS+MTR assumptions, [0.000, 0.072]. If we indicate that participating in the program will not hurt an individual’s “Obese” outcome, it is the Upper Bound that should be replaced by 0, if I understood correctly. In other words, the Lower Bound should remain the same as those in the MTS assumption.

    Click image for larger version

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    Any comments would be appreciated. Thank you!

  • #2
    see McCarthy et al. 2015; page 419- there it says that Y=1 denotes good outcome. So stata will assume that if you when whatever is assigned as Y=1 is a good outcome.
    One way to go about it is like in Millimet & Tchernis (2013), they flipped the outcome variable to notobese from obese then there prob of notobese in control group was higher than in treatment group hence they chose the negative selection results. You can also try to flip your outcome variable to make Y=1 denotes food secure households.

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