Thursday, November 17, 2022

Paired Stats: Using Stats for Multiple Purposes.

 I'm gonna detail the process of how I've been dealing with ability scores for the past few years and put it all in one place I can point back to, because I've had a decent number of discussions about it at this point.

The core of the system, is to have a stat which can be beneficial on either end of the axis. A good visual example of this would be a Size stat.

  • When your Size stat is big, so are you.
  • When your Size stat is small, you are too.
You could make this function as a single attribute, one that you test in order to do big person things, which small people can't do as well (because they're not big).However, this can also test another aspect of your character: how good they are at doing small person things.

The easiest way to model this is with the following relationship:
  • When trying to do a big person thing, roll under your Size score.
  • When trying to do a small person thing, roll over your Size score.
These kinds of stats represent your character in very clear ways, for some examples that aren't Size:
  • Barachus the Barbarian  has a very high Will score of 16, this means he is very independently minded and proud, but maybe finds it hard to connect with others.
  • Lorena the warrior has a less than average Will score of 6, this means she is somewhat easily swept away by fads, and finds it somewhat easy to relate to others through shared experiences.

Handling Derivatives

Many systems operate under a basis of "derived stats" which are pulled from your base stats, which is something that would be difficult to model using stats in this way. So how do you deal with that?

An anydice comparison between standard stat distributions, and generic derived stat distributions.

The easiest way to do it, I think, is to declare the intent of any given derived stat to one aspect of each of your stats. That was a bad way to put it though, what I mean by that is this:
  • Hitting people and making it hurt is something Big people are good at, so instead of an attack stat, you can simply roll under your Size score to make an attack.
  • Avoiding people is something Small people are good at, so instead of a stealth stat, you can roll over your Size score to hide from someone.
  • Assuredness in self is something Proud people are good at, so instead of a Save stat, you can roll under your Will score to subvert your fate by force of will.
  • Understanding of people's motives is something Understanding people are good at, so instead of an initiative stat, you can roll over your Will stat to act first when a negotiation becomes a fight.
There might be a better way to do this, but it's generally easy to apply things to one aspect or another of a given axis.

The Glaring Issue That I hate but Deal With Anyways

Here's the chance a character with a perfectly average and normal Size stat of 10  has to do a big person thing:
  • 50%
Now here's the chance they have to do a small person thing:
  • 55%
Where the hell did that come from?
Well, I'll try and model this with a little diagram, please bear with me.
Because the number 10 is included regardless of whether you're rolling over or under, rolling over will add an extra 5% chance of success to the roll. This still plays nice overall, as the inverse is true for the number 11, both of which are the most likely results of a 3d6 distribution. It does, however, mean that no character will ever have a perfect 50-50 chance of success at a given task.

That's everything I have to say for now.


  1. This reminds of Trollbabe where you have a single stat and you roll under it for fighting and roll over it for magic and I was trying to figure out a wait to expand upon it further. Thanks for doing the heavyl lifting :)

    Do you think it could model Skill vs Talent? So my Agility is 14. I'm great at trained agility actions (14 or less) where my muscle memory knows what to do but I'm not that great at unexpected use of gross movement (14 or higher)? Does that work?

    1. Honestly I think that's a great example of how to use it.