SAS has no facilities for date arithmetic and no easy way to build it yourself. In fact, that's the biggest problem with SAS: it stinks as a programming environment, so it's always much more difficult than it should be to do something new. As soon as you get away from the canned procs and have to write something of your own, SAS falls down.
I don't know enough about SPSS to comment. -- Jeff ______________________________________________ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
