Hello all
I'm doing a difference-in-difference regression to analyse the impact of removing financial incentives from 26 quality indicators, across 450 health clinics.

I have a dummy variable for whether the indicator is in the treatment or control group. (26 in treatment group, 2 in control group)

I also have a dummy (categorical) variable for practice and quality indicator.

In the regression I'd like to absorb the time-invariant fixed effects of each indicator and practice:

Code:
reg Performance Year##Treated i.Indicator i.Practice
The problem is that 'Indicator' is perfectly collinear with the 'Treated' dummy.

What's the best strategy to deal with this is Stata? Many thanks. (I'm using Stata 15).