I have a dataset with the variable id and gcstot ( numerical score). Everytime I am trying to create a new variable using gcstot its giving me an error message that gcstot is uninitiated, even though its already there on the original dataset. The original dataset is as below. I am trying to run the code data trs2; gcs = gcstot*2; run;  It is giving me the output as               gcstot    gcs                        1 . .   Log: Variable gcstot is uninitialized. NOTE: Missing values were generated as a result of performing an operation on missing values. Each place is given by: (Number of times) at (Line):(Column). 1 at 57:13   Dataset obs          id          gcstot 1 13 -1 2 14 14 3 15 14 4 16 15 5 17 -2 6 18 15 7 19 15 8 20 15 ... View more