“Make a skill check to see how much you know about X thing” has typically been a really crappy mechanic in most games.
There’s three typical pitfalls:
- If you roll poorly, you might get no information at all, which often goes against the idea of a highly knowledgeable character
- You might succeed but receive no useful information
- You might fail and the GM gives incorrect information, but because you know the roll was bad, you don’t trust it, so it’s almost the same as getting no information at all.
Apocalypse World solves a lot of this by making their version of the knowledge roll being “Pick from this list of questions, the better you roll, the more questions you get to ask” and the list is broad but nearly always relevant questions.
I’m leaning towards this as a broad, portable set of rules that can go into most rpgs where you might want to make a knowledge roll:
First, your character gets a bit of general context about the situation, object, or topic at hand for free. That may be just a sentence or two, but it does provide some knowledge about it. “These swords are of Eastern make – the warriors all fought from horseback, so the blades are curved to allow slashing while riding by.”
You make a roll. The GM gives you 3 facts about the thing you’re trying to understand/remember etc. Failure means 1 of the 3 facts is accurate. Success means 2 of the 3 facts are accurate. Critical or whatever makes a really good success by this system’s mechanics means you get 3 facts correct.
If there’s some reason your character would have especially good knowledge about the thing in question (“I grew up in a port town, of course I know boats”), then one extra fact is correct – if you failed, you’d still get 2 of 3 correct facts.
So, short of a critical success, you have some space for doubt, but also you have some ideas of things to explore/research/or consider further. This might involve finding experts to verify the truth of some things, compare the facts to evidence, or perhaps use magic or superpowers as a way to confirm things.