# TTRPG system rulebooks scale poorly for learning

There are tons of interesting tabletop RPG (TTRPG) systems out there that aren't Dungeons and Dragons (D&D) that would be cool to try, and I am unlikely to run or pitch any of them because it's such a hassle to when you can just run D&D.

Part of this hassle is that using a new systems scales poorly. Suppose you are a game master (GM) and have an existing group of players who are familiar with D&D. (That's probably most groups of players you could find that are familiar with any TTRPG.) If you want to run a new system for them, first you need to learn the rules well enough to run the game, which takes some amount of time proportional to the complexity of the rules. We can approximate the complexity by the number of pages in the rulebook, \(m\). Then each of your players has to learn the rules well enough to follow along. That takes time proportional to \(n - 1\) times \(m\), where \(n\) is the total number of players including the GM. So, learning the rules alone takes \(\operatorname{\Omega}(mn)\) person-hours.

That's not counting the time it takes for you to learn how the system works in practice. That includes learning how the game most easily flows, as well as learning how to build encounters that are the right level of challenging. That seem s plausibly proportional to \(\operatorname{\Omega}(mn)\), too.

A friend of mine once pointed out D&D is dominant and often used even for scenarios that it is unlikely to work well for, and I think this is partly why. There are large upfront costs to using anything else.

(Of course, there are other reasons. I suspect the problem is exacerbated by the gap in tooling between D&D and other systems.)

Some questions arise from this:

- How badly do additional pages or people increase the time to learn a new system? In technical terms: Big Theta doesn't imply a constant, so is the constant large or small? I don't have much experience trying new systems, but I have some, and I suspect it is large enough to matter. But I can't say how large.
- Are there other more efficient approaches to running new systems from the rulebook that avoid (some of) these large upfront costs?
- Are there workable ways to make rulebooks easier to learn from or get started with?
- Are there easier ways to learn besides rulebooks? (Assuming you don't already have a player who knows the system...)