Bell Curve - Ramifications?

[Christian]

But this brings about the question - why is the game stacked in the PCs' favor? What makes that so?

If you're asking about intentions, it's pretty simple: games with lots of monster TPK's and few party TPK's are much more fun than ones that work the other way around ... The details of how that's arranged are more complex, which is why they pay game designers big bucks. (Cue bitter laughter from game designers.)

 

[Darkness]

It also makes bad for PR for D&D... After all, critical successes would now occur when you roll a "6-6-6" with dice.



But seriously folks, unless you changed the rule, critical hits in combat would become almost non-existant.

Yeah, the rules in UA for replacing d20 with something else suggest modifying threat ranges in order to leave the approximate probability of a critical threat intact.

 

[Mort]

This is the kind of thing that is good to know.

But this brings about the question - why is the game stacked in the PCs' favor? What makes that so?

In the case of D&D - intent. The PC's are supposed to win fights at or bellow (and even slightly-moderately above) their challenge level - this is what makes it a heroic as opposed to a gritty-realistic or a horror game. As such the numbers are stacked in the PC's favor.

 

[GeorgeFields]

Personally, I'd prefer using 2d10. It keeps the natural 20 a maximum, but eliminates the natural 1 as a minimum. It introduced a "bell curve" of a sort (it's more of a bell pyramid, really), that skews toward the average result, but keeps the dice results on the outside edges common enough to still be useful. Plus, it's only two dice to add together.

I'm actually planning on doing this with my next campaign for a while to see how well it works. I just need some players now.

 

[mmadsen]

If you look at a simple spreadsheet of the probabilities we're discussing, you can see that small bonuses can become monumental under a 3d6 system.

For instance, a +2 bonus that takes you from hitting on a natural 11 (or higher) to a natural 9 (or higher) on 1d20 increases your number of hits by 20% (x1.2). On 3d6, it increases your number of hits by 48% (x1.48).

 

[mmadsen]

In the case of D&D - intent. The PC's are supposed to win fights at or bellow (and even slightly-moderately above) their challenge level - this is what makes it a heroic as opposed to a gritty-realistic or a horror game. As such the numbers are stacked in the PC's favor.

Unless they're fighting a big, bad, evil guy above their power level. Then that "helpful" pattern inverts itself. (But the "action economy" kicks in.)

 

[Jeff Wilder]

I'm also interested in getting a feel for how people feel about bell curves, and how they would feel about going from rolling a d20 for everything, to a set of dice and having to deal with a bell curve.

I don't mind rolling 3d6, nor a system designed around a bell curve. It doesn't matter too much to me what action-resolution dice I'm rolling, as long as it's consistent. (E.g., it would annoy me to switch between a d20 and 3d6 when moving between combat and skill rolls.)

One subtler implication of a bell curve is that some players might feel less "excited" about die rolling. The large majority of 3d6 rolls are going to fall within 3 of the mean, which just isn't a lot of variation. IMO, one of the reasons D&D is successful is that the d20 is so random that action resolution feels much more iffy than it actually is. It creates an all but illusory possibility of failure.

D&D mitigates the randomness in combat, for example, by typically pitting PCs against a succession of much weaker opponents. The consequence is that in any given battle those opponents can roll higher than average, or the PCs can roll lower than average, making the combat seem in doubt, when it rarely ever is.

By contrast, GURPS, with its bell curve, makes combat exciting by pitting PCs against opponents who, though of course usually weaker, nevertheless often seriously threaten the PCs.

Just something to keep in mind.

 

[mmadsen]

D&D mitigates the randomness in combat, for example, by typically pitting PCs against a succession of much weaker opponents.

And by handing out lots of hit points.

 

[WhatGravitas]

As a side note, using 2d10 as resolution roll is an interesting middle ground - but the averageis a bit higher (11 instead of 10.5), but the distribution is flatter and swingier than the 3d6.

Cheers, LT.

 

[GeorgeFields]

If you look at a simple spreadsheet of the probabilities we're discussing, you can see that small bonuses can become monumental under a 3d6 system.

For instance, a +2 bonus that takes you from hitting on a natural 11 (or higher) to a natural 9 (or higher) on 1d20 increases your number of hits by 20% (x1.2). On 3d6, it increases your number of hits by 48% (x1.48).

Here is the one I created just to check out various methods.