You’ve probably heard the quote from W. Edwards Deming that
if you can’t measure it, you can’t manage it
Which is an accurate quote. It comes right out of The New Economics. And on the surface, it makes sense. Whether you call it OODA, Plan-Do-Check-Act, or just a feedback loop, how can you control (manage) something if you don’t know what’s going on? And the more accurately you know, the better you can control it. That’s just a basic feedback system.
The thing is, that’s just part of the story. Or really, part of the quote, which is hinted at by that leading lower case i. The full quotation is actually
It is wrong to suppose that if you can’t measure it, you can’t manage it – a costly myth.
Think about the difference between those two quotes. The first is Taylorism. Scientific management at its most basic and most rigid. Measure everything. Then use those measurements to force results. And if you can’t measure it, figure out how or ignore it.
The second is the complete opposite. It’s about being able to manage the situation based on what it is, qualitatively. It’s about knowing where you want to get to and working towards it. Even if you don’t know where you are. It’s about dealing with ambiguity and making progress from a place of ambiguity. It’s about working with the situation we have, not the situation we wish we had.
That doesn’t mean you can’t or shouldn’t use accurate measurements when you have them. Far from it. It’s almost always better when have data to guide you. The more accurate your feedback signal the better you can craft your response. And you should. You should, whenever possible, measure things. Collect metrics from your apps, libraries, and services. You should monitor those metrics and respond to changes. Ideally you measure them well enough to use them not just as indicators of problems, but as predictors of problems so you can respond to them before the problem starts.
But you should also recognize that you need to manage things even without those metrics. It might be because you don’t know how to measure something, or because measuring it would take too much time/effort/resources that would be better spend on something else. For example, you might not be able to tell how much better option A or option B will be, before or after trying them. You might just have a feel for it. But you still have to make a choice. You have to manage the situation. And if anyone tells you Deming says you can’t, tell them The Rest Of The Story.