One mistake organisations make in performance measurement is to not have a real methodology. They treat measuring performance as an ad hoc activity or event. But when you do adopt a performance measurement methodology, another mistake is to do too much too soon. Starting small is important for a few reasons...
Rushing into a full implementation of your new performance measurement methodology, without a strong enough performance culture (and how many of us can claim to have that?), is a recipe for failure:
You'll overwhelm people and burn them out.
You'll make mistakes without noticing, and leave them uncorrected.
You'll feel out of your depth and lack confidence when you need it most.
You'll fail to get a measurable return on investment for your measurement approach.
Starting small, just like a pilot test, has some very worthwhile advantages: