Regarding Difference-in-Difference, I saw a lot of discussions saying that the treatment will receive the value of 1 if on the event day. However, from this paper of Dasgupta,2019, I am wondering if they use the data of the observations on the event day.
I asked this question because in their paper, they did not mention clearly whether they use the data on event day in their study. What they said from section 3.1 is
Figure 1 plots the mean of the mean change in asset growth of treated firms and control firms in the same industry, 2 years before and 5 years after the adoption of a leniency law in a country. Thus, the control firms are all firms in the same industry in countries that had not passed a leniency law in the 7 years surrounding the event date.
I am wondering why they say "7 years surrounding the event"? Whether "surrounding the event date" includes the event date?
For clarifying the question, for example:
If Korea passed the law in 1997, so the treatment including Korean firms in 1995,1996,1997,1998,1999,2000,2001 and the Korean firms in 1997,1998,1999,2000,2001 will receive the value of 1 (post x treatment)
the treatment including Korean firms in 1995,1996,1998,1999,2000,2001,2002 and the Korean firms in 1998,1999,2000,2001,2002 will receive the value of 1 (post x treatment)