@Thompson82 wrote: I need to create a time interval variable that counts weeks for my selldate variable in 2 year intervals. The weeknum variables in the example data are what I am trying to achieve in sas.  Parameters   When working with "time" and "date" values you want to be very careful about terminology. Your values are dates. Dates are measured in days. Time, and datetime, values in SAS are measured in seconds. If you confuse the two, which happens fairly often with beginners, results are sometimes quite odd. ... View more