SAS Tip
of the Month If a=1, b=. (missing) and c=3, then what does the SAS statement d = a + b + c; assign the value for the variable d? The answer is "." or missing as one of the numbers is missing. The correct way of summing the variables and let SAS deal with the missing correctly, i.e. ignore it from the sum, is to use the SAS statement d = sum(a,b,c); This last statement will produce the answer of d=4. 

________________________________ Updated May 1, 2006 