Ask for help about Quantile Control Method (QCM)

[Janvi Fung]

Hello everyone,

I'm currently learning about the synthetic control method and trying to replicate the example provided by Qiang Chen (2024), who developed the command. However, when I attempt to run the placebo tests, I encounter an error that I haven't been able to resolve.qcm

The two lines of Stata code I'm using are taken directly from the original example:

qcm gdp, trunit(9) trperiod(176) placebo(unit cut(2)) frame(growth)
qcm gdp, trunit(9) trperiod(176) placebo(period(168)) savegraph(growth, replace)


When I run them, Stata returns the following error:

option placebo() not allowed
r(198);

Reference: Chen, Q., Xiao, Z. and Yao, Q., 2024. Quantile control via random forest. Journal of Econometrics, p.105789.

[Hemanshu Kumar]

placebo may have been an option available in an earlier version of the command, but has been (deliberately or accidentally) removed from the current version of the command on SSC (v.2.0.1 dated 2024/09/13).

It is a bit odd, because the code in qcm.ado seems to have large chunks meant to deal with the option placebo (see e.g. lines 378-391 and 446-690) but the syntax for the qcm program does not accept any such option.

It might be best to write to the authors to resolve this issue. They may have deliberately removed the option for good reason, and they will be in the best position to tell you how to proceed.

[Janvi Fung]

placebo may have been an option available in an earlier version of the command, but has been (deliberately or accidentally) removed from the current version of the command on SSC (v.2.0.1 dated 2024/09/13).

It is a bit odd, because the code in qcm.ado seems to have large chunks meant to deal with the option placebo (see e.g. lines 378-391 and 446-690) but the syntax for the qcm program does not accept any such option.

It might be best to write to the authors to resolve this issue. They may have deliberately removed the option for good reason, and they will be in the best position to tell you how to proceed.

Much appreciate, I will ask the authors