Comments in SAS can be of the form   /* comment enclosed in slash-asterisk and asterisk-slash respectively */ * comment as per "if the first nonblank character after a semicolon (or when it is the very first character in the entire source code) is an asterisk then everything up to the next semicolon will be treated as a comment" ; %* comment in macro language syntax. Similar rule as before applies, ie. has to be terminated by a semicolon and has to come first after a statement boundary ; Now all this is extremely abbreviated and subject to omissions/errors that my fellow peers will eventually point out. What it boils down to in the context of your question: The "bold statement" is nothing but a comment that tries to explain the non-bold statement (ie. the subsetting if) to its left. Hope this makes sense Robert ... View more