Morgan Housel of the Collaborative Fund draws attention to how information and metrics are always changing:

Investment facts are always changing. But prediction is doubly hard because the facts investors care about and pay attention to—which is what makes facts relevant—change all the time. Not just by industry, but for the market as a whole.

Rarely can you say, “When this happens, that occurs,” because that occurring relies on other people thinking this matters, when their attention may have drifted off to something else.