I have found that the "LINES" statement is producing something called a Compact Letter Display, and that is what I would like to create for pairwise comparisons I make using procedures that do not have an option to produce Compact Letter Displays natively.   SAS clearly has this built-in to some procedures, so it is possible, but it appears to be a more complex problem than I had imagined.   Update: I may have found part of my answer, though I don't have SAS/IML so that poses a problem.  https://github.com/friendly/SAS-macros/blob/master/mult.sas ... View more