Hello everyone,

I would like to ask one question that I am struggling on. I would like to estimate the "Treatment-on-the-Treated effect". There are only two groups - group having the treatment and group having no treatment. (means one treatment group and one control group). Treatment is extension service trainings.
For estimating the TOT effects, I use actual training attendance as the treatment variables. I measure training attendance in tow ways: (1) a dummy variable that takes a value of one if household attended at least one of the training sessions that were offered and zero otherwise, (2) intensity of training attendance, measured by the number of training sessions attended relative to all training sessions offered (takes value from zero to one).
The decision to attend training sessions is endogenous. so to avoid that I am using the instrumental variable (IV) approach. And here comes the struggle. I have never used diff-in-diff approach with IV before.
I wrote a commands:
where group - treatment varialbe, par_a - is (1) method of estimating actual participation, par_b - is (2) method of estimating actual participation.
adoption intensity was how many of "new technology" that household adopted (for example here is how many chickens that households adopted in the follow-up year), takes value from zero to infinity. adoption dummy is whether household adopted or not (takes value of one or zero)

******Treatment on the Treated*******using participation Dummy (par_a)

xtivreg adoption_dummy (group=par_a) i.par_a##i.year, vce (robust)

xtivreg adoption_dummy (group=par_a) i.par_a##i.year $controls, vce (robust)


xtivreg adoption_intensity (group=par_a) i.par_a##i.year, vce (robust)

xtivreg adoption_intensity (group=par_a) i.par_a##i.year $controls, vce (robust)

******Treatment on the Treated*******Intensity

xtivreg adoption_dummy (group=par_b) c.par_b#i.year, fe vce (robust)

xtivreg adoption_dummy (group=par_b) c.par_b#i.year $controls, vce (robust)


xtivreg adoption_intensity (group=par_b) c.par_b#i.year, vce (robust)

xtivreg adoption_intensity (group=par_b) c.par_b#i.year $controls, vce (robust)



And I feel like there are wrong. I would really appreciate the help. Thank you in advance