The problem with this is that it incentives short-term thinking, allowing you to juice the numbers temporarily, and at cost to the metrics that are not currently prioritized. But there's something to the idea.
You’re not told ahead of time what the metrics will be, so you can’t cheat and/or plan ahead other than by being generally good at your job across all likely metrics.
You mean to say that the metrics are applied post-hoc. I.e. you reward last month's efficiency this month.
Otherwise, you incentivize poor performance all the time, so that I can show massive improvement on this month's "efficiency push", next months "productivity (lines of code, completed stories) push", the "bug bash", etc.
