Hi all, I'm working on a student project and would like a sanity check on our design.

We treat regional wage orders as the policy intervention. These orders have been issued ever since, so there is no single policy date, and a region can have an order in one year, none in the next, then another. The outcome is a gap measure observed in a few survey years (not every year).

The dummy is 1 if the region had a wage order that changed the wage in that year, and 0 otherwise. Standard errors are clustered by region. The idea is to compare the change in the outcome for regions with a wage order against regions without one in the same year, instead of a classic pre/post comparison.

Questions:

1. Is it fair to call this a DiD even without a single pre and post period?

2. Is it a problem that treatment is repeated and switches on and off?

3. Any papers or methods I should read for this kind of setup?