Note that the standard errors in those cases is 0, so the calculation will involve division by 0.    Without your data, it's impossible to say what is causing this, but it could be perfect collinearity, I think. ... View more

I'm not sure how that changes anything. You can use the libname function inside a data null step to create the library based on the LT/UT variables.   Why are you creating macro variables outside your process, its better to keep it internal to your process.   data _null_; lts=substr("&lt", 3, 2); uts=substr("&ut", 3, 2); rc=libname(cats(dir, lts, uts)); run; ... View more