How to roll knowledge?

[weckar]

I am often in the situation where players should roll knowledge, but if they fail should not know what type of knowledge is relevant. How do you resolve this?

[Zaq]

Two main ways to solve this.

First, the GM can be the one to do the rolling. Have your party's relevant Knowledge mods on your cheat sheet and do the rolling for them. That way you can tell them what they know without telling them what they rolled when they don't know something. The downside is that it's more work for the GM.

Second, you can let players tell you what kind of Knowledge they want to roll. If it's the right kind, it works at no penalty. If it's the wrong kind, it either works at a penalty (if it's related, like rolling Religion or Arcana when the right answer is Planes) or gives unhelpful/misleading information (if it's wildly unrelated). The downside is that it kind of puts the onus on the player to guess ahead of time what makes sense to roll, so it can be unnecessarily punishing if they happen to have the right skill trained but pick the wrong skill to roll (remembering as always that standard Knowledge checks don't actually take an in-game action), and it also requires that the GM be flexible to account for not just shafting players who happen to make a good-faith guess but guess wrong.

Or you could just tell them "nope, you're not rolling the right thing" and tell them not to metagame. That works better in some groups than others.

[KillianHawkeye]

If you have players that don't metagame too badly, then there's no problem telling them what knowledge check to roll. That's what I do.

If it's an issue of a monster that is disguised as something else, or that just naturally appears atypical for its creature type (like maybe a vampire who can pass themself off as a living creature), in those cases I'd probably follow Zaq's advice to let the players tell me what kind of Knowledge check they're rolling and respond accordingly. You don't have to tell them they rolled the wrong skill, just say they don't know anything useful (just like if they had failed with the correct skill check).

Not all monsters are meant to be easy to identify at first sight, and it's okay to give players incorrect or partially correct information. Like in my example of a vampire, if they were an elf before becoming Undead (which is something that might be readily observable if you can see their face and ears clearly), then a Knowledge (local) check should tell the player information about elves. A good Spot check might reveal that they look a little pale if you want to give them a hint, but I wouldn't give them a Knowledge (religion) check about vampires unless they saw fangs or something else obviously vampiric or had some reason to suspect vampires are a thing to be watching out for.

But for any monster that isn't focused on trickery and subterfuge, just tell them which check to roll. Even do it anyway in some cases. Like if there's a bone golem? Somebody with enough of the right Knowledge (or the right Knowledge in tandem with a good Spot check, like with the vampire) probably can spot whatever differences there are between a bone golem and a skeleton. So you have to use your best judgement on when to tell and when not to in those cases.

[HighWater]

My personal approach is that whenever players want to use a Knowledge check (or I suggest that they should), they roll a single d20 and then tell me what the result would be on each knowledge type on their list (I should be writing their modifiers down as it doesn't change that often...)

This way, they don't have to play the "Which knowledge should I use?"-guessing game (which depends on metagame information so needlessly punishes beginners) nor do they roll a bunch of d20 for each knowledge type they can think of. You get a single chance to know relevant information on a given encounter, it really shouldn't matter if you can guess what arbitrary category the game has organized it in.

[Twurps]

Either you know something, or you don't. I know copper conducts electricity. Did I learn this in chemistry class, or was it physics class? If I can't remember which class I learned it in, do I suddenly not know it anymore?

Translating back into the d&d world. Having to guess which knowledge skill to use makes no sense at all, and it required metagaming by definition, which is also undesireable.

rolling all knowledge skills seperately is one way of working around this, but in quite a few situations will lead to 'inflation'. Knowledge about the king's father might be best portrayed by Knowledge nobility, but knowledge history might also be usefull, as would knowledge local, depending on where the king's father lives/lived. So basically you end up with a 'take the best of 3 rolls' situation where the chances of a low result are greatly diminished.

So the best way to handle this is to allow 1 roll either like this:



First, the GM can be the one to do the rolling. Have your party's relevant Knowledge mods on your cheat sheet and do the rolling for them. That way you can tell them what they know without telling them what they rolled when they don't know something. The downside is that it's more work for the GM.

Or like this:

My personal approach is that whenever players want to use a Knowledge check (or I suggest that they should), they roll a single d20 and then tell me what the result would be on each knowledge type on their list (I should be writing their modifiers down as it doesn't change that often...)

This way, they don't have to play the "Which knowledge should I use?"-guessing game (which depends on metagame information so needlessly punishes beginners) nor do they roll a bunch of d20 for each knowledge type they can think of. You get a single chance to know relevant information on a given encounter, it really shouldn't matter if you can guess what arbitrary category the game has organized it in.

We use Zaq's approach for really crucial rolls, and Highwater's for most others. Our group is good at 'not metagaming' so for trivial stuff our DM also will sometimes just tell us which knowledge to roll, and we won't use that information if the roll is too low.

[Segev]

I usually give a list of knowledges that might apply, and let anybody who wants to roll each and tell me the results. I tend to use degree of success rules with knowledge in general, and will give results for each kind of knowledge. Sometimes misleading if they’re operating on too little information and have knowledge that points in the wrong direction. Not to deceive, because I’ll tell them when it’s just their best speculations.

[Efrate]

I ask for a combination of knowledges generally, usually 3, and have different dcs. A weird planar breech might be dc 20 planes, 25 arcana and 30 religion or something. Creature ids i just say its a religion or whatever if someone wants to attempt it.

[Darrin]

You need to create a range of information based on the margin of success. Look at the later Monster Manuals for examples. Roughly: DC 5 you learn it's an animal with a bite attack. DC 10 it has fangs that inject poison. DC 15 you know it's a nerve toxin that targets Dex. DC 20 you know it's vulnerabilities and defenses. DC 25 you know the entire stat block. DC 30 you know what it had for breakfast and it's Netflix password.

If you scale the information correctly, if the party rolls low, they still get enough info so they know where to go for follow-up research. For example, knowledge check fails horribly on an ancient book, but at the lowest margin of success, you can tell them it looks like the language is a dialect of Elvish. Party can now ask each other, "Hey, do we know any really old Elves?" and presumably they then know where to go to get the information they "failed" to get.

At least, that's the theory. In practice, the party ganks the ancient Elven seer before he can tell them anything, kills half the city guard, gets thrown in prison, breaks out, starts an interdimensional war, destroys the indestructible MacGuffin, and half the party dies because "it's what my character would do."