Hi, I'll preface this by saying that I am new to macros.  I want to use them because I am working with a sas data set that has over 100 variables, and roughly 40 of them have Yes/No values that I need to convert.  I want to convert these Yes/No values to 0/1 values, and I'm having a lot of trouble getting the informat to work.  I've created a macro variable (&YesNovars) that contains all of the variables I want to convert.  The data step below runs without error, but when I look at the data, nothing has changed.  Any help is greatly appreciated! Here is what I've tried: proc format library=library;    invalue $yesno 'Y'='1'                  'N'='0'                       ; run; data bicc.maternal12; set bicc.maternal10; attrib &YesNovars informat=$yesno.; run; Thanks! ... View more