Saturday, April 05, 2025

Proposal: [Appendix] Weighting the dice

Append a new paragraph to the Appendix rule “Random Generators”:

If a rule requires that a value is selected “weighted randomly” from a set of options, each of which has an integer weight, the choice is made by posting a Dice Roller comment that contains a list of the options with positive weights (with each option’s weight specified alongside the option itself) and a roll of DICEN (where N is the total of the positive weights). Nothing else that could be confused for a list of options with weights, or for the dice roll, may be included in the comment. The selected option is determined from the dice roll result and list as follows: if the sum of the weighs of the first x-1 options on the list is strictly less than the dice roll, but the sum of the weights of the first x options on the list is greater than or equal to the dice roll, then the xth option is selected. (The sum of the weights of the first 0 options is 0.) It is not possible to make a weighted random selection unless at least one of the options has a positive weight.

I think this algorithm for making a weighted-random choice works, and it avoids all the scams I’m currently aware of. Although Josh suggested making it a Building Block, there is an obvious place in the Appendix for it.

Comments

SingularByte: he/him

05-04-2025 03:04:31 UTC

for

Darknight: he/him

05-04-2025 03:06:15 UTC

for

Clucky: he/him

05-04-2025 03:27:45 UTC

How does “If a number or other game variable is selected “at random” or “randomly” from a range of possible values, its value shall always be taken from a uniform probability distribution over the entire range of possible values, unless otherwise specified. This value must be determined by an appropriate roll in the Dice Roller, unless otherwise specified, and which value the roll result corresponds to must be reasonably inferable from the nature of the roll and any comments supplied by the Nomicer making the roll before or while making the roll. If a selection is explicitly specified as being “secretly” random, the Nomicer making this determination may do so using a private method of their choosing, instead of the Dice Roller.” not already cover this?

ais523:

05-04-2025 03:46:55 UTC

@Clucky: Empirically the exisiting rule doesn’t successfully cover this case because players have historically been unwilling to write proposals to make weighted dice rolls without trying to specify how (even though such specifications have been doing more harm than good, as we saw recently).

It’s also written in terms of weights rather than probabilities, which are generally easier to use in rules (and work around problems like Josh’s “what if the Dice Roller probabilities aren’t exactly correct?” that came up during my DoV).

I don’t mind too much if players decide that this is unnecessary (even though Josh explicitly requested it in the belief that it would be necessary, he may have been wrong).

Clucky: he/him

05-04-2025 04:18:50 UTC

I worry a bit about the “the choice is made by posting a Dice Roller comment that contains a list of the options with positive weights”—I guess it doesn’t hurt to keep it there.

tentative
for

Raven1207: he/they

05-04-2025 04:28:15 UTC

for

DoomedIdeas: he/him

05-04-2025 04:33:41 UTC

for

Zack: he/him

05-04-2025 05:48:17 UTC

against I feel like this is unnecessarily prescriptive for a common phrase which already has an unambiguous statistical meaning, and honestly it’s a little too verbose and confusing for me personally to the point that I would have trouble following it.

Clucky: he/him

05-04-2025 06:04:08 UTC

against cov

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