"Metrics" are defined as the science of measuring. When you're trying to evaluate complex systems, finding the right metric can be tricky. Take your health for example. You could measure your health by taking your temperature, testing your cholesterol level, evaluating your body mass index, determining your white blood cell count, or probably a hundred other ways to measure how healthy you are. Finding the right set of metrics to define whether or not a person is healthy is quite complicated.
Similarly, measuring the quality of a computer programmer is hard. You could measure them by how many lines of code they write, but the best programmers often write the least code. You could measure them by how many features they build, but if they pound out tons of features along with tons of bugs, you've got a crappy programmer.
If you pick the wrong metric, then you're potentially rewarding the wrong type of behavior.
I bring this up because Hank and I were chatting the other night about a couple we know who are going through some marital difficulties. I took the opportunity to size up our relationship.
Me: So, you getting ready to dump me?
Hank: Nope. I'm sticking around.
Hank: Well, I thought about it and I realized that my life with you is better than it would be without you.
Me: Hmmmm. So, what you're saying, is that in order to keep our marriage intact, I just need to make sure that your life without me would be worse than your life with me?
Hank: Yes. Exactly.
Me: Now THAT is a metric I can work with.
Do you understand what this means? I don't have to make my wife happy. I just have to convince her that life without me will be at least 1% worse than life with me.
I could, for example, strap a series of explosives to Daisy and then wire the detonator to a dead man's switch that I would hold in my hand at all times. If Hank tried to end our marriage, or incapacitate me in any way, BOOM! Hank's life is suddenly much worse!
I gotta tell you, finding the right metric for a successful marriage has been quite a relief.