SAS Tip of the Month
Your program has a variable that is coded as 1=YES and 2=NO with an associated format called YN. Now there is a new value of 3=DON'T KNOW in your data but the format YN has not been changed. In your reporting program you can create another format, in this example YNX, using the following code:
proc format; value ynx 1='YES' 2='NO' 3="DON'T KNOW"; run;
A better way though, avoiding transcription problems, is to make the new YNX format by nesting the old format YN into the new as shown in the following code:
proc format; value ynx 3="DON'T KNOW" other=[yn.]; run;
Note that you must enclose the existing format name in square brackets, as shown above, or with parentheses and vertical bars, for example (|yn.|).
Hope this is useful. See you next month.
Updated July 2, 2014