Hello all
I'm assessing the impact of an intervention over the course of two years (from 2016-17, and from 2017-18).
I'm using a difference-in-difference analysis, comparing the treatment group to a control group over three years: pre-treatment (2015-16) and post-treatment (2016-17 and 2017-18).

I'd like to calculate the DiD in coefficient for both the change over 2016-17 and then 2017-18. I can do this simply by separating my data into two databases, with 2 time points each (one to compare 2015-16 to 2016-17, and a separate database to compare 2016-17 to 2017-18). In each case, I have a dummy variable which equals 0 in the earlier year, and 1 in the later year. I also have a dummy for whether the variable is in the treated or control group. I then regress the outcome variable over Time##Treated.

I would like to do both comparisons using a single database, as this would be more succinct and less clumsy. I'd also like to show the cumulative effect of the intervention over the two years. Is it possible?
Many thanks.