If you can't measure it how do you know it exists? That is at least half of my point, the other half being you can't assume a specific course of action is neces

If you can't measure it how do you know it exists? That is at least half of my point, the other half being you can't assume a specific course of action is necessary and proper without demonstrating the harm actually occurred. That you think harm might occur is not enough, you need to show it has occurred (and can probably use proof of past harm to show that inevitable harm will occur). Your example is disingenuous because a cockpit instrument by definition monitors something you want to pay attention to. We can measure and record many things, most of which are probably irrelevant to many problems and their solutions.