Dear all,

I am currently trying to define my first panel data set in Stata. For this, STATA (14.2) wants me to define a Panel ID variable and a Time variable. In my panel dataset I am looking at company transactions over 20 years. Accordingly, it happens that a company has also made more than one transaction per year. This brings us to the problem: Defining the panel ID variable is not a problem, since I can simply use the unique company ID, but when I define the time variable, STATA shows me the error that per time variable, i.e. in my case per year, each panel ID may only occur once.

Various scientific papers also consider several transactions of a company per year and still were able to calculate for example xtlogit, fe or xtlogit, re. When I do this, above error message appears from Stata. One way to handle this problem - as far as I know - are multilevel analysis (mixed, melogit). But this does not correspond exactly to the logic xtlogit, fe or xtlogit, re. Another solution approach would be to aggregate the data so that I only have one transaction of a company per year but this would distort my calculations.

Thus, how it is possible to run a xtlogit,fe or xtlogit, re in such a situation? How can I handle the definition problem with the time variable?

Thank you very much for your supprt!