I was recently having a discussion with Paul Kedrosky and Deva Hazarika about weight, and it reminded me of my own aversion to scales. I have literally no idea what I weigh, I've avoided them for over twenty years, and if I ever have to be weighed for a checkup, I don't look at what the result is. This is because numbers have power. If I start measuring my weight, then even small daily or weekly gains will make me anxious. The stress is counter-productive because it saps my morale and reduces my motivation to stay fit and eat well.
I'm a particularly obsessive person when it comes to goals, which is why I've learned to be careful what targets I use. Maybe other people find watching their weight helpful, but looking at the people I know well leaves me wondering if it works for anyone? If you think about it, nobody's end goal is to lose weight. What we actually want is to be healthier, fitter and sexier. There's better measures for all of those than raw mass, whether it's cholesterol levels, running times or just checking yourself in a mirror.
A quote I'll always remember from an undergraduate course is "You start off measuring what you value, and end up valuing what you measure". Any time that we reduce a complex situation down to a single number, it distorts every action we take. We judge results by that metric, so anything it doesn't capture gets neglected.
My sister worked at a call center for years, where they were measured primarily on how many calls an hour they dealt with. She told me her colleagues would hang up on long-winded customers – apparently if you do it while you're talking, people assume it was a glitch. The numbers looked great, despite the harm it was doing the business.
If you watch the stock market prices every day, you'll sell low and buy high. The emotional response to seeing the numbers fall gets hard to resist, as does the greed when they've been rising for weeks. What you actually care about is how much money you end up making, but the stock ticker doesn't capture that. It's why the average investor's returns are so much lower than average investment returns.
If you pay a programmer based on how many lines of code she produces, and you'll get incredibly verbose code with more room for bugs.
Is measuring your weight helping or hindering you from reaching your real goals?