A number is useful until it replaces the goal
Write the goal next to the number, list how chasing it could backfire, and review the warning on a schedule.
Curiosity Chronicle · The Cobra Effects of LifeThe man who tracked his sleep, his morning routine, and his money found the numbers were starting to run his life instead of improving it. A sleep score stood in for a healthy life, and a bank balance stood in for freedom. His answer was not to stop measuring, but to keep each number tied to its purpose.
His tool is a single sheet of paper. He puts the number on one side and draws an arrow to the real purpose on the other, then keeps that page where he will see it often, so the number cannot quietly stand in for the purpose.
On the bottom of the same page, he lists the traps that chasing the number could create, and the early signs that they are showing up. He uses a line from investor Charlie Munger: "All I want to know is where I'm going to die, so I'll never go there." It means find the traps first so you can steer clear of them.
He then revisits the page on a set schedule, monthly or quarterly. Because no plan survives first contact with the enemy, he says you need to trust your ability to adjust more than your plan or intelligence.
Falling into the trap of letting a number replace the goal is almost unavoidable, but you can catch it early. Begin with a single sheet for a single number.
Questions people ask
Where should I keep the sheet?
Keep it where you will run into it without trying, such as on a mirror, refrigerator door, or the front of a notebook. The point is to see it every day. If you stop noticing it, move it to a new spot.
What does backfire from a measure look like?
In his account, a morning routine grew to fill an hour before real work began, and money goals showed up as another quarterly target met but an anniversary dinner missed. Those are the kinds of costs he means. Look for life shrinking to serve the number.
How often should I do the check-in?
He calls for a simple monthly or quarterly check to ask whether any of the warnings you wrote down are appearing, and how to adjust if they are.