Productivity is just aggregate output of the economy divided by the number of people-hours worked. You can argue about if that's a useful thing to measure or if the measurements themselves are accurate or if you should capture more of the output, but at root it's very simplistic. If you can use AutoCAD to generate more drawings than using paper which you (or your firm) sells for the same price per drawing, then your productivity did go up. Is that meaningful? Less certain.