Where would you put the idea of checking the quality of your source of hypothesized patterns?

I admit this list of possibilities is just what seems reasonable to me.....

Patterns you've observed yourself in a culture you've spent a lot of time in and that you've needed to update now and then, patterns you've heard about from members of a culture, patterns you've heard about from people you observed updating on new evidence, patterns you've observed with no surprises, patterns you've heard about from people who mostly seem to talk to each other about a culture they're not part of, patterns you've seen in fiction.