I read a piece the other day on the use of productivity measures for academic staff. The measures were all about output quantity (presumably with the proviso that papers wouldn’t be published if they didn’t meet quality criteria). However what matters is not quantity of output or quality of output but the impact of that output - how is thinking or practice changed as a result. 

This is difficult to measure as truly innovative and original ideas could take years to achieve their full impact. But attempting to judge it - even subjectively - might be a better measure than simply counting it. 

The same is true in your business. If you measure the wrong things, you get the wromg behsviours from your employees.

Productivity measures can be quite difficult to establish in certain contexts but we should be as creative with our measures as we are with our productivity improvements.