Amazon is famously run by studying and responding to its own data; yet when it comes to promotions, decisions are often subjective and guided by human emotions and petty political dynamics.
Validation is easy - you run your site through a validator, and it's either valid or it isn't. The rest of the stuff, such as whether my logo or the biggest headline should be the h1 in my HTML, isn't so easy and is subject to interpretation.
It is very difficult to make a vigorous, plausible, and job-risking defense of an estimate that is derived by no quantitative method, supported by little data, and certified chiefly by the hunches of the managers
The movie business is very much like that: people in authority making purely emotional decisions instead of interesting rational ones.
There's more to research than just looking up facts. Eventually, you have to make subjective calls. If you're writing a science fiction novel, there's probably some speculative technology in it. You'll have to decide how to project existing technology forward in a plausible way.
Football officiating is so subjective - much more subjective than any other sport. But the more I watch - and I watch too many matches - the more impressed I am with referees.
We don't have some message from God that gives us a list of what's good and what's not good. Obviously, we have to make our own flawed judgments about each thing.
