Jenny, who is the audience of this concise message you're crafting? I think that will determine how you frame this.
For now though, here's a brain dump:
Performance measurement is the process of designing the best evidence of the degree to which a goal or result is being achieved, as time goes by. It's a powerful way to keep us focused on our goals, and to guide us to make the best improvements to reach those goals, sooner and with the least effort.
This could be a good thing for us all to do, as an elevator pitch about what performance measurement is really about.
Smiles, Stacey.