D&D 5E Advantage / Disadvantage in 5e

[Gecko85]

These guys got it wrong, or at least, not what I was looking for. The 94% answer provides the percent chance that you'll roll any particular number, which isn't a comparison of two numbers. It also includes the probability that at least a particular number will be rolled, which again, isn't the difference between two rolls (which would be the bonus earned).

The second-best answer also asks: what are my odds of getting a certain result with two dice? Versus: what is the average distance between two die results?

Gecko, I think your new results are skewed because, for one thing, they assume that there is an average 16.625% increase in your roll, even if you roll 20.

The link I provided gives the percent chance of rolling a particular number *or higher* if rolling two dice and choosing the highest. That's precisely what advantage is. The average bonus I calculated is just that: an average. Your target number won't always be the same. Yes, it's different for each number. I provided an average, since you had previously done the same. Here are the bonuses by target number:

1: 0
2: 0.95
3: 1.8
4: 2.55
5: 3.2
6: 3.75
7: 4.2
8: 4.55
9: 4.8
10: 4.95
11: 5
12: 4.95
13: 4.8
14: 4.55
15: 4.2
16: 3.75
17: 3.2
18: 2.55
19: 1.8
20: 0.95

 

[Nebulous]

PS - Does the rest of this thread say that it takes ONLY ONE disadvantange to negate all advantages? Because that is not how I read the rules at all.

Yes, i'm pretty certain one disadvantage or advantage completely negates the other(s).

 

[Mark CMG]

PS - Does the rest of this thread say that it takes ONLY ONE disadvantange to negate all advantages? Because that is not how I read the rules at all.

Yes, i'm pretty certain one disadvantage or advantage completely negates the other(s).

Advantage and Disadvantage

Sometimes a special ability or spell tells you that you have advantage or disadvantage on an ability check, a saving throw, or an attack roll. When that happens, you roll a second d20 when you make the roll. Use the higher of the two rolls if you have advantage, and use the lower roll if you have disadvantage. For example, if you have disadvantage and roll a 17 and a 5, you use the 5. If you instead have advantage and roll those numbers, you use the 17.

If multiple situations affect a roll and each one grants advantage or imposes disadvantage on it, you don’t roll more than one additional d20. If two favorable situations grant advantage, for example, you still roll only one additional d20.

If circumstances cause a roll to have both advantage and disadvantage, you are considered to have neither of them, and you roll one d20. This is true even if multiple circumstances impose disadvantage and only one grants advantage or vice versa. In such a situation, you have neither advantage nor disadvantage.

When you have advantage or disadvantage and something in the game, such as the halfling’s Lucky trait, lets you reroll the d20, you can reroll only one of the dice. You choose which one. For example, if a halfling has advantage on an ability check and rolls a 1 and a 13, the halfling could use the Lucky trait to reroll the 1.

You usually gain advantage or disadvantage through the use of special abilities, actions, or spells. Inspiration (see chapter 4) can also give a character advantage on checks related to the character’s personality, ideals, or bonds. The DM can also decide that circumstances influence a roll in one direction or the other and grant
advantage or impose disadvantage as a result.

Section in bold.

 

[Reynard]

FWIW, I do not count Advantage vs Disadvantage. I look at the whole situation and decide whether a character or creature is in an Advantageous, Disadvantageous or neutral position. For example, by the book if if a character was fighting at night in knee deep mud but one of his allies was grappling with an enemy, I would still rule disadvantage because those circumstances far outweigh the grappling advantage, IMO. I make this practice clear, of course, at the beginning of a session at a con or whatever.

 

[Coredump]

The issue is how 'valuable' is getting advantage. So if you needed a 16 to hit, would you rather have advantage on the roll, or a +4 on the roll?
As it turns out, you are better off with the +4. (Advantage would be the equivalent of a +3.75 on the roll) The benefit from advantage is never better than a +5 on the roll, and can be worse than a +1.

The numbers below are accurate.

The link I provided gives the percent chance of rolling a particular number *or higher* if rolling two dice and choosing the highest. That's precisely what advantage is. The average bonus I calculated is just that: an average. Your target number won't always be the same. Yes, it's different for each number. I provided an average, since you had previously done the same. Here are the bonuses by target number:

1: 0
2: 0.95
3: 1.8
4: 2.55
5: 3.2
6: 3.75
7: 4.2
8: 4.55
9: 4.8
10: 4.95
11: 5
12: 4.95
13: 4.8
14: 4.55
15: 4.2
16: 3.75
17: 3.2
18: 2.55
19: 1.8
20: 0.95

 

[Gecko85]

The issue is how 'valuable' is getting advantage. So if you needed a 16 to hit, would you rather have advantage on the roll, or a +4 on the roll?
As it turns out, you are better off with the +4. (Advantage would be the equivalent of a +3.75 on the roll) The benefit from advantage is never better than a +5 on the roll, and can be worse than a +1.

The numbers below are accurate.

Yes, but if you need a 15 on the roll instead of 16, you're better off with advantage (+4.2).

 

[fjw70]

Trying to recycle a good threadname here...

I just ran some numbers, and I'm seeing that advantage is MORE than an average +5 to your roll. It's +6.65.

In a game of Bounded Accuracy, that's huge.

Here's how I got the number:[sblock]
Roll two d20s, and you get 400 possible outcomes. Of those outcomes, 20 give you the same result on the die, so they're +0. Of the rest, there are no negative bonuses, because you always take the higher number. So on one end, there are 38 ways to get a +1 out of advantage. On the other, there are only 2 ways to get a +19 bonus out of advantage. Add all the bonuses from all the outcomes together, divide them by 400, and you get 6.65.[/sblock]

Let's put it this way: if you have advantage on a check, you get the proficiency bonus of a 20th level character, plus 0.65, on average.

Is my math wrong? Does advantage seem reasonable in this light?

One flaw in this methodology is that you are assuming the lower roll is the "normal" roll and the higher one is the "extra" roll gained by advantage.

 

[Henry]

In a system with by-design max modifier limits, extra rolls are the only way to assert significant modifiers while still keeping those maximum upper and lower limits of modifiers (intentionally avoiding the term "bounded accuracy" because I have seen people misunderstand it before).

One thing I used to complain about with 3e a decade ago was the number inflation compared to earlier editions - for the majority of a character's life, the numbers usually didn't get into so high and low that they completely outstripped the dice, because there was a max THACO and a max AC. (Past about level 12 that was no longer true, but in 1e and 2e I don't think I ever played a single game past 10th level, so we always had a reasonable "bound" to follow.) Rarely was a character i ever saw rolling over effectively a +14 to +15 to hit, and if the bonus to damage made it above the die size, that was because there was a whole lot of min maxing going on. I love advantage and disadvantage and am glad they incorporated it.

 

[Rhenny]

Another reason why advtg/disadvtg was used was that it opens up design space for other special features that grant bonuses (like Bardic Inspiration, Bless, etc,). With both methods, there is more variety, and it is rare that a player or DM will have to do longer calculations adding too many modifiers.

 

[fjw70]

In a system with by-design max modifier limits, extra rolls are the only way to assert significant modifiers while still keeping those maximum upper and lower limits of modifiers (intentionally avoiding the term "bounded accuracy" because I have seen people misunderstand it before).

One thing I used to complain about with 3e a decade ago was the number inflation compared to earlier editions - for the majority of a character's life, the numbers usually didn't get into so high and low that they completely outstripped the dice, because there was a max THACO and a max AC. (Past about level 12 that was no longer true, but in 1e and 2e I don't think I ever played a single game past 10th level, so we always had a reasonable "bound" to follow.) Rarely was a character i ever saw rolling over effectively a +14 to +15 to hit, and if the bonus to damage made it above the die size, that was because there was a whole lot of min maxing going on. I love advantage and disadvantage and am glad they incorporated it.

An AD&D character could get a +14 or 15 to hit. A 10th level fighter's THACO was effectively a +9 and add in magic weapons, and strength and specialization bonuses would get you into that range.