How do I assign a start date?
I have a longitudinal study with sites entering on different dates. To make them comparable, I need to assign each entry date as "1" and the second data collection point as "2" and so on. The data are in long format and there are a lot of missing data (missed data collection) The data look like this, I want to generate "Count": ID Date Var1 Count 001 Jan-1 . . 001 Feb-1 . ...
marcokunzelmann
ngonzalez0