As a GM, how should I handle cases of "relevant knowledge" among my player-characters? For example, if someone is playing a Doctor (with Healing at a d10, say), surely they don't have to take "Knowledge (Medical Instruments)" to be able to use a scalpel. I'd imagine they wouldn't even have to roll anything: it's just assumed, given their character, that they know how to use basic instruments.

But what about things that they could easily not know at all, but that if they did know, it's simply because of that main skill? For example, how would you game-out whether a Doctor character recognizes another Doctor from having read their research, or whether a Sailor character is familiar with the layout of a certain kind of ship?

In both cases, that knowledge isn't necessarily assumed as part of the character's skillset, but it seems cumbersome to spend advances on "Knowledge (Peer Research)" or "Knowledge (Mid-Sized Freighter Layouts)" just in case they're needed.

Would you just have them roll the skill itself? "Roll a Piloting check to see if you've served on a vessel like this"? Or would it just be GM's discretion, "yeah you've met this guy at a conference, you don't need to roll"?

How would you handle this?


There are a number of different mechanics at work here....

Common Knowledge

This is used to represent basic background knowledge a character may have because of where they were brought up, what they do for a living etc. This is not a skill, and is checked with a simple Smarts roll. Depending on the exact character background, a modifier can be added to this roll if they are particularly likely/unlikely to know the information in question.

Specific Knowledge

This is covered by individual Knowledge skills such as Knowledge(Chemistry), and represents a deeper specialization in a particular area of expertise. You need to be careful when adding these to your game to ensure that they will have significant impact and get used regularly in whatever setting you are playing in. One guideline is that if a specific skill isn't important enough to be rolled at least twice per session, it should be handled by Common Knowledge instead.

Practical Skills

These are all the other skills that represent actually doing stuff.

So taking your particular examples...

A doctor with Healing who is using a scalpel as part of trying to heal someone just makes a Healing roll. If they are doing something more trivial under little/no pressure and without any other special circumstances, I would be usually assume they just succeed. This is particularly the case where there is no interesting consequences for failing, but then that is a good general rule for deciding whether to roll at all. A professional doctor would also probably have Knowledge(Medicine), representing their theoretical knowledge of the subject.

Establishing whether a doctor PC knows a particular doctor NPC can be done in a number of ways depending on what you as GM want to achieve. If its interesting/important to the plot, then just say they do, no roll required. If you think a roll is appropriate, I would use Common Knowledge in this instance, as this would represent their background knowledge from their job. If they had Knowledge(Medicine) as well, I might allow a roll on that with a +2 bonus for being more specialised. To increase player buy-in to this whole process, once it's been established that they do know them, you can ask the player how this is. Getting players to answer questions like this encourages them to fill out their character's back story, and is good at ensuring the PC's are strongly linked into the fictional world.

My answer for the sailor character would be the same as for the previous example.


You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .