Regarding "strict exogeneity" assumption, I found a discussion here:it means that conditional on observing the data, the expectation of the error term is zero, which is something relating to confounding variable.
However, today, I read a recently published paper of Miller,2021 and see in Reviewing DID Assumption part, he said that parallel trend and strict exogeneity are key assumptions.
I am wondering why the author did not mention the "no anticipation effect" assumption, which is one of the important assumption (Assumption 2 in Borusyak, 2021) in staggered DiD, especially when examining the impact of a law on an outcome variable there?
