Dear Statalists,
I have a quick question, please.
I have an unbalanced panel dataset over a period from 2000 to 2010. A standard was issued, and accordingly, firms started to adopt these standards, but the adoption is not compulsory, I mean there is no specific cut-off point, where the adoption process was simultaneous. To clarify, a group of firms adopted in 2005, while others adopted in 2006, and so on.
I am using the generalized DID, and I have read that there is something called parallel trend assumption and based on what I understood that I can investigate the parallel trend assumption when the adoption at a specific cut off point, but I think I can’t use it in my case because there is no specific cut-off point. Do you think I am correct?
Thanks.