d20 vs 2d20

[jaelis]

Here is a chart to illustrate the difference.

Blue points are for a contest, where the bottom axis lists your bonus to the roll minus your opponent's. This is the chance to win outright, not tie.

Orange points are the chance to beat DC 11, with the given bonus. For a different DC, just offset the bonuses, so DC 15 with a +5 bonus is the same as DC 11 with a +1 bonus.

As you see, the main difference is that the contest is more random. You are more likely to beat an opponent with a much bigger bonus then you are to succeed against a really high DC.

 

[jmucchiello]

Yes, there's something really important that you're overlooking:
The fact that most of the people who've ever played, & will ever play, this game DON"T CARE about this "problem" you perceive.

Thank you for being so positive. The first sentence of my post says "There is no right answer." I know most people don't care. Most of those people never heard of ENWorld and would never even consider posting here. But those of us who are here are the kinds of people who MIGHT CARE. And thus, those are the people I'm posting to. So thank you for contributing whatever you think you did to the DISCUSSION.

 

[jmucchiello]

Grapple checks are d20vd20 and are combat checks.

Thanks for this fact. Grapple checks are the only combat checks that are skill checks.

I think I am missing something - where does the 39 come from? If you roll d20 vs. d20, there are 400 possible outcomes. Are you thinking of the sum of the dice? I don't think the sum is relevant to two d20s rolled as a contest.

39 is the number of possible states of outcome. You roll 7, I roll 10 is the same as 6/9, 5/8, 4/7, etc. There are 39 possible differences: -19, -18, -17, ... 17, 18, 19. Only one outcome is -19. Only 2 outcomes are -18, 3 are -17, etc. And that's what forms the triangular distribrution.

 

[jaelis]

Thanks for this fact. Grapple checks are the only combat checks that are skill checks.

Well, and shoves. And the DMG has rules for disarming.

 

[jmucchiello]

I think the distribution does matter vs static DC exactly because it changes the probability of success and failure, if we roll 2d10 instead of 1d20, the probability of success vs high DC or failure vs low DC will be significantly smaller.

OTOH I don't actually think that the triangular distribution of the difference in opposed rolls matters, because for those rolls by default it's not the difference that matters, but just who scores higher.

Well the fact that the swing of possible outcomes changes is what first bothered me. A d20 has 20 possible outcomes 1 to 20. But the 2d20 difference has outcomes from -19 to +19. Why should skill checks (and grapple rolls) have more swing than swordfighting and dodging fireballs? It's a difference lacking a reason. Speed of play matters in combat but not in grapple checks?

So far "Tradition" seems to be the only reason.

 

[CapnZapp]

Again, what is the issue?

 

[jmucchiello]

Well, and shoves. And the DMG has rules for disarming.

Arguably, shoving is just a form of grappling. Traditionally, both stem from those weird tables in the 1e DMG where grappling and bull rushing (and pummeling) were separate combat systems.

 

[LordEntrails]

Its done the way it is for ease of play. As shown, the statistical difference is negligible. Opposed rolls are there because of tradition, and the sense that in those situations both opponents are "active" and when the player is the active defender they are going to want to have a say in what happens. i.e. they want a roll themselves to help defend themselves in an opposed strength check or grapple, etc.

Their is no problem other than having two systems of resolution (which are still intuitive) and a perception that things are not the same, when they effectively are.

 

[5ekyu]

Its done the way it is for ease of play. As shown, the statistical difference is negligible. Opposed rolls are there because of tradition, and the sense that in those situations both opponents are "active" and when the player is the active defender they are going to want to have a say in what happens. i.e. they want a roll themselves to help defend themselves in an opposed strength check or grapple, etc.

Their is no problem other than having two systems of resolution (which are still intuitive) and a perception that things are not the same, when they effectively are.

"and when the player is the active defender they are going to want to have a say in what happens."

So isnt that also just as relevant when he is trying to avoid a sword or a fist as an open hand shove or trip?

Having played it in 5e for quite a while with pcs always being the active party (players roll vs static npc values) i have seen no problems and yes... The players live having the active part on them, not the npcs.

 

[Morrus]

Yes, there's something really important that you're overlooking:
The fact that most of the people who've ever played, & will ever play, this game DON"T CARE about this "problem" you perceive.

Do you feel better for that?