Hello I have two data sets, they both have the common variable person_ID. One dataset consists of the date on which people where arrested before a treatment effect, the second data set consists of the dates people where arrest after a treatment effect was given. I want to merge these data sets. The problem I run into is the way the variable person_ID was coded.For example there is a person in this data set that was arrested at three distinct dates, he is given the ID 1, so this person appears as 1 three times in the data set. In the second dataset this individual was arrested twice so in the merged data set 1 should appear 5 times. When I try the command merge is fails to merge in any of the possible combinations. If this was unclear please tell me and I will clarify.