Friday, 21 November 2014

When Many Adventurers Do One Thing

Sometimes the efforts of many add neatly, as when many arms try to lift a gate.

Other times, they add imperfectly, as when many eyes try to sight or many ears to hear. It's a mix of varying factors: what's being sensed "out there" and the individual's attention. The individual can only contribute so much.

Other times, additional hands are useless, as when picking a lock, or downright counterproductive, as when many people try to hide or sneak.

In a game, very few skills add neatly except for the sheer application of brute force. Those that add uselessly should be obvious. Which leaves the imperfect and the counterproductive situations to deal with.

So when adding skills imperfectly (and why not, there are diminishing returns even when opening a door because only so many people can get good leverage):

One person = one check
2-3 people = 2 checks
4-7 people = 3 checks, made by the 3 best people
8-15 = 4 checks, made by the 4 best, and so on.

Each power of 2 adds another check.

And when skills interfere - as when a large group is trying to sneak:

One person =one check
2 people = 2 checks
Up to 4 people = 3 checks, made by the 3 worst people
Up to 8 = 4 checks, made by the 4 worst, and so on.
Up to 16 = 5 checks and so on.

Failure by any one means noise is made or they can be seen.


  1. Seems like there is a typo.

    Up to 4 people hiding 3 checks by 3 WORST
    Up to 8 people hiding 4 checks by 4 BEST


  2. I don't think that quite works, there are plenty of tasks that no one person can do that become possible with multiple people. Having 8 people try to shift a stuck car out of a snowbank isn't at all the same as 8 tries by a single person. A lot of tasks are better modeled as additional people providing a bonus or penalty to a single group check, allowing for better (or worse) results than any one can achieve. Individual checks are best reserved for things where the tries really are independent (sinking a free-throw in basketball, say).

    1. Yep, that's why I gave the example of lifting a gate as something that is additive. My actual system in 52 Pages describes these tasks as having a required number of "strengths" to do where an average person contributes one, +1 STR bonus contributes 2 and so on.

    2. That seems reasonably, and a lot quicker than taking the log of the number of people and rolling that many checks... My game had some rules that worked kind of like that (spreading attacks across more and more folks reduced them a level for every doubling) but players found it more trouble than they were willing to deal with, even with me doing the math.