My tinkering with Fourth World has required some analysis of the probability of the Aid move.

My tinkering with Fourth World has required some analysis of the probability of the Aid move.

My tinkering with Fourth World has required some analysis of the probability of the Aid move. Results (and Python code) are available here:

19 thoughts on “My tinkering with Fourth World has required some analysis of the probability of the Aid move.”

  1. Lester Ward, I used something similar to your Fourth World approach for a while (basically: 7+ Aid ==> “step up/down,” but 7-9 leaves you exposed).

    It definitely addressed the fact that Aid in RAW is a bad bet. But I found that it ended up stealing the spotlight from the Aid-ee and putting it on the Aid-er, particularly when we allowed folks to Aid after the roll.

    E.g. Player A does a thing, rolls a miss, Player B jumps in to Aid and gets a 7-9, and we end up focusing on Player B’s Aid and ramifications while Player A is sorta in a limbo state. And in the end, Player A doesn’t feel like they did the thing, it feels like Player B did.

    That’s less of an issue if you’re strict about “declare and roll AID before the main roll.” But that’s not usually how I’ve seen players use Aid at the table.

  2. Interesting.

    What I’ve been using so far is making the aid-er roll 1d6 and allow the aid-ee to replace any of its dice with the aid-er dice (I’m allowing roller before or after, since it doesn’t “bump up” per say).

    Didn’t study what are the statistical ramifications of this, but in play, it seemed to keep the focus on the character doing the action and not on the aid-er.

  3. Addramyr Palinor yeah, that’s pretty much what I’m using now. Basically: grant advantage on the main the roll, but you’re exposed to consequences. Works really really smoothly and I’ve found that it encourages aiding quite a bit.

    The probabilities are mostly equivalent to a ~ +1.5 to the roll, so it’s definitely a better probability bet than standard Aid. But it comes with higher stakes, too, because now you’re both exposed.

    For after-the-fact Aid, I limit it to a +1 modifier, (with the GM telling you the requirements/consequences up front). That means we only think about Aiding after the roll on a 6 or a 9 (or rarely on an 11), which works out to be about 1 in 4 rolls. This keeps post-roll Aid uncommon, and it’s a fairly easy table interaction. “Yeah, you can jump in and help, turn that miss into a 7-9, but you’ll both be exposed to his attack. Do you do it?”

  4. Yeah, but I find that its more involved if the aid-ee actually rolls. To me it feels more like the PC is helping actively (and when he rolls poorly, it’s also easy to see how despite his intention, he actually don’t provide much help at all).

    That’s with the mindset that rolling die is fun 😛

    The second approach mentioned by Jeremy is the less time consuming though. You actually only go to dice when it matters (on a 9 or a 6).

  5. Lester Ward the “harm”? You mean the hinders instead of the help?

    I don’t use that at my table but I’d do the same I guess. Roll a d6, you can force the “hinder-ee” to replace one of his dice (namely the best) with yours (if you roll lower).

  6. Jeremy Strandberg, what you are talking about is really two different aid moves, with different triggers. One is the “when you help out before a roll is made” and the other is “when you help out after the fact”.

    I think I may make the Fourth World aid move be “before-only”, then give the after the fact move to the aid-focussed discipline, the air sailor.

  7. Lester Ward yup, it’s totally two different triggers. I put them under the same heading, but your idea of limiting the after-the-fact aid to a specific class… that’s a great idea.

    The biggest grumble I’ve heard from folks (not actual players, just folks online) about the Aid-as-advantage move is that it’s a mechanical outlier… it’s the only place a “roll 3, keep 2” situation comes up. I think that’s a fair argument (aesthetics are important), but I also think that the ability to let the Aid-er roll the advantage die (which we also do) is a pretty big selling point. Like Addramyr points out, it makes everyone feel involved.

    Also not following what you mean by “the harm part of the move?” If you mean Interfere, I’ve split that out into a different move as well:


    When you try to foil another PC’s action, say how and roll +STAT (ala Defy Danger). On a 10+, they must pick 1. On a 7-9, they must pick 1 but you are left off-balance, exposed, or otherwise vulnerable.

    * They do it anyway, but take -2 forward

    * They relent, change course, or otherwise allow their move to be foiled.

    It’s worked really, really well in play.

  8. Oh, and as an FYI… I recently ran a one-shot where all +1/-1 modifiers (well, almost all) were replaced with advantage/disadvantage.

    It was… really great, actually. I’ll probably post more about it in the next couple weeks.

  9. I was sort of assuming you had done that. If you use advantage/disadvantage anywhere, it makes more sense to use it everywhere. (Among other things, this prevents weird stacking of bonuses: you either have advantage or you don’t.)

  10. Well, for Stonetop we don’t currently call it advantage when you Aid, but it’s advantage. And my players have never objected to it as a one-off mechanic, but observers/reviewers have.

    Which, yeah, does sort of open it up to possible stacking issues. But it’s really hasn’t been an issue.

    Turns out, though: there’s a lot of design space that advantage opens up. Some places we applied it that I wouldn’t have originally thought of:

    * Volley >> 7-9 choice >> “You have take what you can get; deal damage with disadvantage”

    * Defend >> instead of “deal damage equal to your level” >> “deal damage with disadvantage”

    * Cleric buff to healing (which I moved to a background move, based on deity): when you cast Cure Wounds, you get advantage on the healing roll.

    And I found that moves that would historically have been a “+1 to do X” are a lot more appealing when they’re “you have advantage to do X.” So, like, I gave the Thief a move called Move Silently, Hide in Shadows: when you Defy Danger by being stealthy, you have advantage.” Something about that extra die makes it feel more potent, even though it’s mechanically not much of a difference.

  11. Jeremy Strandberg Just bought Legacy 2e and this is what they’re doing. It felt super D&D 5e-ish but it’s actually the only single innovative mechanic of this system and certainly a very nice idea.

    Was wondering how it felt in a pbta game, though.

    I certainly often lose track of all the +/- 1’s

    Do you track them as in Legacy?

    They use Data (basically you write to what subject you can spend a point to gain Advantage).

  12. For the things that granted advantage “forward” (like Discern Realities) it wasn’t significantly different. For the things that regularly, reliably granted advantage (like that Move Silently, Hide in Shadows move), it seemed easier for the players to remember. (It was definitely easier for me.)

  13. I was thinking about this discussion and came up with a version where you roll the 1d6 and then force them to take it. Now what is interesting about that is you may cause the opposite effect, like making their roll worse when you were trying to make it better (ex. they roll 5 and 3, keep 5, and you roll 1, shifting a result of 8 to 6 — full probabilities below). Since that is built in, I thought “why roll anything else at all?”


    When you act to assist or obstruct an ally in a meaningful way, say what you are doing and roll 1d6. If you assist them, they replace their lower die with yours. If you obstruct them, they replace their higher die with yours. It may not always work out the way you intend.

    What do you guys think?

    The equation works out as b[2d6]+1d6. Here’s how the probabilities compare:

    +1 = [6- : 28%][7-9 : 44%][10+ : 28%]

    b[2d6]+1d6 = [6- : 25%][7-9 : 48%][10+ : 27%]

    Advantage = [6- : 19%][7-9 : 45%][10+ : 36%]

  14. Huh. That’s pretty interesting, Jason Shea. It’d be worth trying out.

    I think it’d work best in a game like Funnel World, Freebooters, or World of Dungeons, where you don’t have the same assumption of competence that you have in core DW. Because it feels more… bumbling? Like, I (the Fighter) try to help you fight but OOOPS I ROLLED A 1 and you rolled boxcars and now I’ve just totally herp-a-durped your move up.

    Similarly: I try to stop you! But I roll a 6 and you rolled snake eyes and now I Jar-Jar-Binks you into mixed success.

    I mean, it doesn’t have to be that extreme, but that’s how the numbers feel. At least when you’re rolling +BOND on standard Aid, if you screw things up you can sorta justify it as “we don’t work well together.”

    But in a game like Funnel World (in particular) where you really are just kind of bumbling along… that might be perfect.

  15. Jeremy Strandberg that description just makes me want to play it more, hehehe.

    I agree that it would fit well in those games, but I think it could also work with DW. You’re more likely to not change the result or make it better than worse. Since you aren’t rolling anything else, the times you botch it takes the place of a 6-. It is a bit more scripted in that whatever happens causes the opposite of your intent, which, I would argue, honors the fiction and the involvement of the aiding player. The fact that your failure affects the other player is in keeping with exactly what the move is about: relationship — you’re getting involved for better or worse (just like real life, ha). How goofy it feels is up to the fiction, the tone of the game, and the GM. The irony of it could be bitter or humorous.

    I guess the question is, “How would it look different than what you as a GM would do when a player rolled 6- to Aid?” With this it is “turn their move back on them” and “reveal an unwelcome truth.”

    Feel free to disagree, this is all just theorizing. I’ll have to try it and see how it goes, though my group may not be the best testing ground as they always want a lighthearted tone. I don’t think those moments would phase them at all (they’d probably enjoy ’em).

    If any one tries it, let me know how it goes.

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