I am familiar with how to do a Difference in Differences (DiD) but have never had to compute a confidence interval for it. I'm curious how one might go about that?
As an example, here is some made up data:
input ID time group value;
1 1 1 1
2 1 1 2
3 1 1 1
4 1 1 3
5 1 1 2
I'm wondering if someone could help me to correctly identify whether certain variables should be considered fixed or random effects.
Just as context, I have a dataset of people (with information about them that I know is FIXED).
I have a variable indicating to which healthcare practice...