d20 vs. the Dice Pool… or is it?

Overheard on The Forge :: d20 vs. 3d6, regarding “linear curves”.

D20 combat is really a die pool system (rolling multiple dice and counting sucessess) in disguise. You roll so many to-hits on single d20s in any given combat that, over the course of a battle, you get a reasonable normal distribution of expected results. Where d20 breaks down is when it shifts to non combat where the entire task is handled with a single roll, and you don’t get this faux pool effect. This is why Take 10 and Take 20 were invented [and, Doyce would add, rolling to Assist…] to patch the weakness of using linear single-rolls for everything other than combat […] increasing the likelihood of getting the expected result.

And… they’re right. One of the things I’ve realized that I really like about the games that I’m currently looking over is that they’re ALL either (a) dice pool mechanics or (b) single-dice mechanics with a means of earning re-rolls or (c) both.
I’ve always liked dice pools — ever since Shadowrun 1 came out. (Roll and add: not so much.) Really negates the chance of Being Good and Sucking Anyway — if you’re good at something, you’re adding not only to your skill, but actually affecting the odds of rolling good numbers.


  1. That’s a really interesting observation (and probably blindingly obvious for a stats person).
    I’ll note, though, that it’s a very bumpy dice pool, even in combat. It’s way too easy for a single crit or fumble to majorly bollix you up. It’s smoother, though, than, as noted, a single “Gather Information” or “Bluff” or …
    Hmmmm. Wonder if there’s a way to retrofit some of those things. “Okay, you’re Xth, level, so roll X D20s …” Nothing quite a crude as that, but …

  2. Dunno… *I’d* certainly never thought of it, but it’s true. (Once again, I find a ‘mechanic’ that’s actually just window dressing.)
    Trollbabe introduces rerolls as a way of getting rerolls on those ‘single roll’ events, which you pay for by putting yourself at risk (you miss, fine… you miss a reroll, your injured in some way) — The Adventures of the Brave Knights that linked to a few days ago does something similar in that you either get success or you can Buy Success if you’re close by taking some ‘damage’ to your character.
    Seems as though something like that might work in d20 skill tests. Hmm.
    Rerolls instead of those infamous die-bump certs. Hmm. Hmm.
    Just seems like there should be someway to work that into the resolution mechanic.

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