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Sometimes, players get advantage; sometimes, monsters get disadvantage. Sometimes it's not clear whether to give someone advantage or his opponent disadvantage, especially in improvised contests (PHB 195).

I know enough about statistics to know that "roll two, take highest" can produce tricky results. Therefore, I ask:

In a contest with otherwise constant bonuses, is giving one side advantage always equivalent to giving his opponent disadvantage?

This could matter e.g. if a player maneuvers a monster into an unfortunate situation. Now it feels better for the player to gain advantage, when more logically the monster is at a disadvantage.

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Yes, all other things being equal, giving disadvantage to one side is mathematically equivalent to giving advantage to the other side.

Anydice link.

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We're looking for long answers that provide some explanation and context. Don't just give a one-line answer; explain why your answer is right, ideally with citations. Answers that don't include explanations may be removed.

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    \$\begingroup\$ I think this answer needs some additional detail. To anyone not already familiar with AnyDice, it isn't inherently clear what that page is illustrating. A verbal explanation of why the two situations are mathematically equivalent will improve this answer significantly. \$\endgroup\$ – Dan Henderson Oct 19 '15 at 21:08
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    \$\begingroup\$ Also this only applies in contested rolls not in combat. I know the question specifies but I think it's worth emphasising anyway lest anyone hastily generalise. \$\endgroup\$ – Jack Aidley Oct 20 '15 at 14:56
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    \$\begingroup\$ The binary nature of advantage is a HUGE exception to the plain arithmetic. Passing over it makes this answer less useful than confusing. \$\endgroup\$ – Bleep Oct 20 '15 at 18:42
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    \$\begingroup\$ This doesn't really answer the question in a useful way unless you're familiar with AnyDice. Also it's just a link, which could go down. The information would be more useful if it were here. \$\endgroup\$ – Jason_c_o Oct 20 '15 at 21:31
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Possible exceptions:

  • The player already has advantage; granting them advantage again does nothing, but imposing disadvantage on the monster does.

  • The 'Lucky' feat allows the underdog with disadvantage to go from "roll two, choose the worst" to effectively "roll three, choose the best".

  • Asymmetry: Stopping the bad guy from doing something might be more important than you doing something (particularly if the rest of the party can do it instead/as well)

  • The odds of criticals shift immensely: it's nearly impossible to crit with disadvantage (1/400).

  • Sometimes granting advantage/disadvantage triggers side-effects: e.g. Sneak Attack.

  • In a multi-competitor contest, advantage might help against everyone, whereas disadvantaging your opponents might be on an opponent-by-opponent basis.

But most importantly:

  • Disadvantage makes the monster suck. Advantage makes the character awesome. Go for awesome!
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    \$\begingroup\$ Also, they are only equivalent when there are exactly two factions and exactly two outcomes. Any situation with more complexity and nuance, then the advantage and disadvantage are not identical. \$\endgroup\$ – LindaJeanne Oct 19 '15 at 16:53
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    \$\begingroup\$ As I understand it, Lucky lets you reroll. So with disadvantage, you roll two and take the worst then roll a third and take the better of that roll and the worst of the original pair. Its not quite as good as best of 3, and probably not as good as best of 2, but it's certainly better than worst of 2. \$\endgroup\$ – Theo Brinkman Oct 20 '15 at 16:47
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    \$\begingroup\$ In a contest, the odds of a critical hit with advantage are not important, because when the enemy has disadvantage his odds of a critical miss increase. Chance of success thus stays the same. \$\endgroup\$ – DaFluid Oct 20 '15 at 16:59
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    \$\begingroup\$ @TheoBrinkman Lucky might be kind of broken \$\endgroup\$ – DaFluid Oct 20 '15 at 17:00
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    \$\begingroup\$ These are useful, but it just starts with "possible exceptions". Exceptions to what? Exceptions to Miniman's answer? I think I know what you probably mean, but it could use some clarification \$\endgroup\$ – DCShannon Oct 21 '15 at 4:25
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I think the one big point that's been glazed over is it depends on the number of attacks (or rolls) on both sides.

If we're talking about two relatively equal "things" (ie two fighters of about same level), it's probably not going to make any different.

However, let's look at a more "extreme" side case to see what I'm getting at.

Let's assume you're fighter (with 2 attacks) is up against a creature with 4 attacks.

Giving disadvantage to the creature with 4 attacks will tend to have a bigger impact on the fight, than advantage to the fighter with less attacks.

In short, the more rolls (not just attacks - that's just a simple example in this case), the more influence.

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  • \$\begingroup\$ lol. love the obligatory downvotes and no feedback ... :\ sigh \$\endgroup\$ – Ditto Oct 19 '15 at 19:43
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    \$\begingroup\$ In this case it's probably that the answer can't stand alone. It's not a good answer by itself; it's an edge case. It's like if you asked "Is STR better than INT on a barbarian?" and someone answered "One thing everyone else forgot is that McGuffin X lets you add INT to damage with Greataxe attacks by left-handed characters." Sure, it might technically be true, but it doesn't really answer the question. \$\endgroup\$ – gatherer818 Oct 20 '15 at 1:37
  • \$\begingroup\$ @gatherer818: thanks, yeah, I post this kind of thing as a comment, and it gets comments "post that as an answer", so I post an answer, and get the opposite ;) Can't win sometimes .. lol It's why I stated it the way I did - already accepted answer - and I'm not contesting it .. just adding info/thoughts on exactly that, an "edge" case. shrug Cheers! \$\endgroup\$ – Ditto Oct 20 '15 at 22:14
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    \$\begingroup\$ @Neuneck: where does it say "all other thigns being equal" ? I'm not seeing it? it mentions "constant bonuses" .. that's a big leap between those two .. and why I talked about multiple rolls (not a difference in bonuses) \$\endgroup\$ – Ditto Oct 20 '15 at 22:16
  • \$\begingroup\$ @Ditto Whoops, indeed I didn't put it there explicitly, just other bonuses being constant (to not make the statistics any more compliated). Still I referred to contests, not attacks. \$\endgroup\$ – Neuneck Oct 21 '15 at 5:53

protected by Oblivious Sage Oct 20 '15 at 15:51

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