Hi
I want to determine what is the type of each entity, based on period of first observation. for example if "a" , first time appeared in first period its new in this period and old in other later periods and if "c" first time appeared in second period, it will be new in this period and old in later periods. it would be something similar to this:
Code:
* Example generated by -dataex-. To install: ssc install dataex
clear
input float period str1 entity float(new old)
1 "a" 1 .
1 "a" 1 .
2 "a" . 1
3 "a" . 1
1 "b" 1 .
1 "b" 1 .
1 "b" 1 .
3 "b" . 1
end
So, How can I do something like that with this database?

Thank you