Paul already corrected your problem with column input. But you have another problem waiting to happen. You have named your last variable MRI, and then your second data step has the line:

MRI=MRI_Count;

where you have no variable MRI_Count ! This is either a misprint, or else you will have trouble here as soon as you try to use the values of MRI. You should rename the variable in your first data step to whatever you want to call it, rather than make a new variable with the same value [and, in your case, get the assignment statement backwards so it won't work].

For that matter, there's no reason you can't put your formula for RATIO in the *first* data step and completely drop the second data step.

HTH, David -- David Cassell, CSC Cassell.David@epa.gov Senior computing specialist mathematical statistician