Im currently working on a research paper for one of my classes. I have data from 2007 to 2017. I wanted to do 3 difference in difference analysis to see if there has been an affect.
first: 2007-2009 with a date in april 2008 being the policy
second 2012-2014 with a date in feb 2013 being the policy
third 2015-feb 2017 with a date in july 2016 being the policy
since my data set is for the full ten years how do I only look at those periods within my pre and post treatment variables? ex) how do I code the dummy variable to be 0 from jan 2012 to feb 2013 only and 1 from feb 2013 -2014? How do I avoid stata reading pre 2012 and post 2014 as 0 and part of my untreated data?