PbtA Dice Odds, for whom it may concern: Although it’s tempting to consider the 7-9 range in AW as being the most likely due to our well-drilled acknowledgment of the 7 as the apex of the 2-12 bell curve, that range spans only 3 numbers, which narrows its likelihood to exactly the same as the failure range which spans 5 numbers (note this is without modifiers):
2-6 = 41.67%
7-9 = 41.67%
10-12 = 16.67%
The curve shifts dramatically with a bonus, though. A 7-9 becomes the most likely once you’re at +1 or above, if I remember correctly.
Yup! And with a +1 the odds of failure are the same as the odds of full success:
3-6 = 27.78%
7-9 = 44.45%
10-13 = 27.78%
With a +2 it’s the inversion of the +0 table, with partial and full success being even:
4-6 = 16.67%
7-9 = 41.67%
10-14 = 41.67%
With a +3 full success becomes dominant:
5-6 = 8.34%
7-9 = 33.33%
10-15 = 58.34%
-1 is terrible, +0 is bad, +1 is okay, +2 is good and +3 is amazing.
Even without any bonus, your odds of some kind of success (7-12) are better than even, 58.33%. This alone makes any PbtA character pretty darn competent.
For a more desperate, harrowing game, you could apply a -1 across the board, or (equivalently) make the thresholds 2-7, 8-10, 11+. This gives a base 58% chance of failure.
In a game I’m working on, I’m ditching the bonuses and instead using die-types for traits a la Cortex. The 2d6 is replaced by two dice grabbed from two trait categories, like Stats and Skills. Those traits range from d4 to as much as d12 with a baseline of around d8. So you could be rolling d8 + d10 or d4 + d8 or any number of combinations. The range changes to 7- fail, 8-11 partial, 12+ success.
I have a feeling this would play havoc with probability analysis.
Interesting, Cam Banks! Wouldn’t be too hard to work out a probability distribution for each possible dice combination. 10 combinations if you go up to d10. 15 if you go up to d12, I think.
I’m resisting opening a spreadsheet, got work to do first… 🙂
Cam Banks Maybe at the table, but otherwise not. Dice probabilities are pretty easy to compute.
Sounds like a really good alternative though.
I’m just afraid of the swinginess. As As If notes, the PbtA baseline mechanic is finely balanced around the 2d6 and small but significant mods. This opens it way up.
Given that you roll into result categories and do not directly use the value rolled, I suspect that it won’t actually feel that swingy.
Still, you won’t know until you try it out. Keep me posted 🙂
Sub’d (as something I should get into to know what to expect from the characters in my games). Thanks.
Cam Banks I had some thoughts about using a similar idea in a hack I was working on. Are you concern that it skews the idea too far from AW’s success and fail mechanism?
I realized that it doesn’t matter if the pool is opposed by a similar pool, but it does matter if you want a flat range like AW.
AW has no real concept of difficulty numbers, really. The range is always fixed. I figured if you remove bonuses and just change the size of the dice you can introduce some interesting tricks connected to manipulating die types into the moves.
Well I can’t wait to see what you come up with.
Hi Cam Banks
I made spreadsheet with probability calculations for this ‘dice modifiers’ for you.
https://docs.google.com/spreadsheets/d/1bmnVOWnj0qNZQ5EMJU7q49RXSLEUvsOCkKD53X4fZQY/edit?usp=sharing
+0 is basically a 50/50 chance of being competent, untrained, in moderate conditions, with a little time, and motivated by the desire to do or die… at something you’ve at least thought about doing before (hence it’s part of the chosen playbook.)
…seems legit.
Note also that, the results are usually not a binary Yes/No… and are provided a;
(Yes, and… because you are exceptionally advanced at this…)
Yes, but… choose some properties that help you narrate how…
Maybe, but… it will probably cost you, or not be the most delightful outcome, if you don’t loosen your grip…
Not really… and, things are getting worse, because…
to do it, do it ~ so, my Gunlugger does a moonsault over Rolfball’s head, from the roof of his car.
well, not really… and, though I did dismount from the roof of the car, and make it over Rolfball’s head, looks like wild flailing does not impress him… he tripped me… mid-air… with a long-spikey-bat… and I busted my arm, sprained my hip, and fractured my shinbone… but, I did manage to clip him in the jaw with a booted heel at the last minute! …I think he’s just getting mad.
Down four harm directly to the body for being self-abusive, and he likely soaked the knocked jaw… He looks like he is just getting started, and I’m out past 6 o’clock… I’d rather meet my curfew than continue fighting — time to change strategies. Parley?
but, you gotta admit… it was an EPIC fail!!!