To create a treatment dummy variable in DID analysis

[Kyle Lee]

First of all, please understand that it may be difficult to understand because I am not good at writing English.

When DID analysis using 'didregress' or 'xtdidregress' in Stata17, is it correct that the value of the treatment dummy in the data is given as 1 only when the observation is in the treatment group and post treatment periods?

Conversely, should I understand that if the observation belongs to pre-treatment periods, whether the treatment group or the control group, the value of the treatment dummy is given to zero, and if the observation belongs to post treatment periods, the value of the treatment dummy is given to zero?

[Jared Greathouse]

See my example of this, coded on line 3 on this post. Treated is coded as 1 if the unit is 17 and greater than or = 1975, any observation not meeting that criteria is 0.