D&D 5E Does D&D Next need +2/-2 modifiers?

[Lokiare]

I have not studied the latest playtest in that detail, so could you please point me to two examples where this happens, where a [insert class] gives up an attack to get Advantage?

The Fighters "Dirty Trick" does something like this. It gives up potential damage to grant advantage on the next attack.

The Monks choice of using a Ki point on an additional attack for Flurry of Blows or using the point to grant advantage on all attacks from Flurry of Blows also counts.

Channel Divinity Abjure Enemy gives up an attack to impose disadvantage on a target.

I'm sure more can be found in the closed play test, or in the supplements they will pump out at a speed of about 1 per month.

 

[Ashkelon]

I actually think next has too many +X modifiers already. I thought the point of advantage was to simplify the game and get rid of all the fiddly numbers from 3e and 4e. We already have conditional bonuses from bards, clerics, wizards, druids, feats, that can all stack and are above and beyond the advantage/disadvantage system.

 

[pemerton]

The Fighters "Dirty Trick" does something like this. It gives up potential damage to grant advantage on the next attack.

There is, at least currently, no way to simply apply superiority dice as bonus damage.

Dirty Trick permits either bonus damage (d6, or d10 from 15th level) or advantage on the next attack, if the die roll equal or exceeds the target's WIS mod.

The worst-case for trade-off is if the target has a +6/+10 WIS - in that case, if I roll a 5 (or 9) I get that much damage, whereas the higher roll confers advantage.

So is advantage on an attack worth 5 (or 9) bonus damage?

Let's compare 1st and 15th level.

At 1st level, to hit is (say) +1 for Prof and +3 for Stat, or +4. Damage, let's say, is 1d8+3, or 15/2.

So when is advantage worth +5 to damage?

The relevant equation can be worked out as follows:

At 1st level, the increase damage expectation from attacking with advantage has to equal or exceed 5 damage.

For a given AC, chance to miss equals (AC-1-bonus to hit)/20, or at 1st level equals (AC - 5)/20. (The additional -1 is because a roll equal to the AC hits rather than misses.)

The chance to hit without advantage therefore equals 1- (AC-5)/20, = (25-AC)/20.

The chance to hit with advantage equals 1 - ((AC-5)^2)/400.

The additional chance to hit, with advantage, therefore equals 1 - ((AC-5)^2)/400 - (25-AC)/20,

= (400 - (AC-5)^2 - 20(25-AC))/400

= (400 - AC^2 +10AC -25 -500 + 20AC)/400

= (30*AC - AC^2 - 125)/400.

For an AC of 13, this gives an extra chance to hit of 0.24. For that to be worth 5 damage, expected damage on a hit would have to be almost 20 and 5/6ths. Conversely, if expected damage on a hit is 15/2, then advantage on the attack is comparable to +1.8 damage.

The effective bonus to hit peaks at AC 15 (the derivative of the above equation is (30 - 2*AC)/400, which equals zero when AC = 15). At that rather high AC, the bonus chance to hit = 0.25. At which point advantage on the attack is comparable to +1.875 damage.

So at 1st level, Dirty Trick is really not that effective: given that few creatures will have WIS bonuses above +1 or +2, it's analogous to a little bit less than +1 or +2 to damage. I'm not sure I want to say it's a trap choice, but it's not making a huge contribution to damage output.


At 15th level it's no better. Let's say the bonus to hit is now +5 (prof) +5 (stat) +1 (magic), or +11 overall, and damage is 1d8 +5 (stat) +1 (magic), or 21/2.

The chance to hit without advantage is now 1- (AC-12)/20, = (32-AC)/20.

The chance to hit with advantage equals 1 - ((AC-12)^2)/400.

The additional chance to hit, with advantage, therefore equals 1 - ((AC-12)^2)/400 - (32-AC)/20,

= (400 - (AC-12)^2 - 20(32-AC))/400

= (400 - AC^2 +24AC -144 -640 + 20AC)/400

= (44*AC - AC^2 - 384)/400.

For an AC of 13, this gives an extra chance to hit of just less than 1/20. That is worth around 0.5 hp of damage. For an AC of 15, it's about 1/8th, hence a bit more than +1 to damage.

The effective bonus to hit peaks at AC 22 (the derivative of the above equation is (44 - 2*AC)/400, which equals zero when AC = 22). At that extremely high AC, the bonus chance to hit = 0.25. At which point advantage on the attack is comparable to just over +2.5 to damage.

Because the chance to hit actually scales faster than opponent AC, at least in the current playtest, Dirty Trick actually becomes weaker at 15th level, because the 1d10 means you're more likely to get advantage, which is not as strong as +1 or +2 damage from the die. I think that does count as a trap. Maybe [MENTION=66111]Cybit[/MENTION] can comment on whether this has been addressed in more recent versions of the rules.

The Monks choice of using a Ki point on an additional attack for Flurry of Blows or using the point to grant advantage on all attacks from Flurry of Blows also counts.

This is a bit mathematically ugly: when is 2 attacks with advantage better than 3 normal attacks? Assuming a 16 DEX for the same to hit chances as the fighter above, we are asking when

2*(1 - ((AC-5)^2)/400) >= 3 * (25-AC)/20. (The average damage doesn't matter, as it is constant across the two options, so only expected number of hits counts.)

40*(1 - ((AC-5)^2)/400) >= 75-3*AC

400 - (AC-5)^2 >= 750-30*AC

-400 + (AC-5)^2 <= 30*AC - 750

AC^2 - 10*AC + 25 -400 +750 - 30*AC <= 0

AC^2 - 40*AC +375 <= 0.

(AC-15)(AC-25) <=0

So only if AC is 16 or above is advantage on 2 attack actually superior to 3 attacks. (At AC 15 they're equivalent. At AC 14 or below 3 attacks is superior.)

This reminds me of Power Attack: what looks like an option but in many cases really isn't one, and hence we have a trap for new players. I think they would be better off rid of it: make a decision about how you want to handle Flurry, and implement that. Alternatively, make it so that you can only spend the point on Supreme Flurry if you've already spent a point on normal flurry.

The possibility that a mathematically weak player might make the mistake of thinking that his/her 2nd level option is more powerful than the 1st level one, when for most ACs you'll face at that level it's actually weaker, is to me quite frustrating and a sign of bad design.

I haven't done the maths, but the 2nd level option will only get weaker at high levels - just as Dirty Trick gets weaker for the fighter - because the benefits of advantage decrease as the bonus to hit scales faster than AC, whereas an extra attack is a 3/2 damage multiplier. (Until 8th level, at which point it's a 5/4 damage multiplier and the maths has to all be redone. I'll leave that to someone else. And I hope monk players enjoy their quadratic equations!)

Channel Divinity Abjure Enemy gives up an attack to impose disadvantage on a target.

I don't think that's right. Abjure Enemy imposes the frightened condition, which is an immobilising debuff. And Vow of Enmity grants advantage on attacks for 1 minute, and as far as I can see doesn't require an action to use.

 

[Ichneumon]

Numerical modifiers apply when the core implement you're using to make the check (weapon, yourself, etc) has its effectiveness directly affected. Hiding from someone doesn't actually make your aim better, so you don't get a straight bonus. Cover, the only thing in 'How to Play' that grants a bonus, does so because a wall or tree makes you directly harder to hit - it's like a second shield. Another example is Great Weapon Fighter, where you can deliberately worsen your aim to get a harder strike. Almost all direct modifiers happen because a player chooses a class or feat option.

Situational +x/-x bonuses work when you've directly modified what you're checking with. For everything else, there's Mastercard ... Advantage/Disadvantage, that is.

 

[Thyrwyn]

Dirty Trick permits either bonus damage (d6, or d10 from 15th level) or advantage on the next attack, if the die roll equal or exceeds the target's WIS mod. . .

Might the value of Dirty Trick increase when one considers that it can be used to negate disadvantage? I'm too sleep deprived right now to run the math.

 

[pemerton]

Might the value of Dirty Trick increase when one considers that it can be used to negate disadvantage? I'm too sleep deprived right now to run the math.

Perhaps.

If you've got a 50% chance to hit (say, +4 vs AC 15) then disadvantage drops that to 25%, or half expected damage. At that point Dirty Trick does become more valuable: your expected damage rises from (say) 15/8, or about 2 hp, to 15/4, or about 4 hp. That's analogous to a +2 bonus that you can impose after hitting, or a +4 bonus that is itself subject to the 50% chance to hit.

I still think it's very fiddly, with hard maths to work out what's going on, and I'm not sure that in its current form it's adding a lot to the game. (Whereas I wouldn't say the same about Spring Away or Trip, both of which give you benefits pretty incommensurable with damage, and hence not giving rise to the same fiddly maths worries.)

 

[Lokiare]

Wow, I think this is the first time many people have agreed with me...

 

[Cybit]

Perhaps.

If you've got a 50% chance to hit (say, +4 vs AC 15) then disadvantage drops that to 25%, or half expected damage. At that point Dirty Trick does become more valuable: your expected damage rises from (say) 15/8, or about 2 hp, to 15/4, or about 4 hp. That's analogous to a +2 bonus that you can impose after hitting, or a +4 bonus that is itself subject to the 50% chance to hit.

I still think it's very fiddly, with hard maths to work out what's going on, and I'm not sure that in its current form it's adding a lot to the game. (Whereas I wouldn't say the same about Spring Away or Trip, both of which give you benefits pretty incommensurable with damage, and hence not giving rise to the same fiddly maths worries.)

I wouldn't read too much into the details of specific abilities, I think they were more concerned with "do people see using superiority dice as a way to do nifty things as good". The math behind a lot of the original abilities was iffy, but from my understanding that was known, and I think you'll see a lot more of the 4E style powers wrapped up in superiority dice.

Also, in situations where enemies need to be finished off, advantage becomes more useful (if they have a handful of HP left, for example).

 

[Sadrik]

I think the advantage/disadvantage mechanic is a very good one. I think separating out exactly what it affects is the key to the 5e game design. It needs to be consistent if you are mixing apples and oranges advantage/disadvantage and modifiers, there better be a rhyme and a reason. Otherwise, it winds up being a hodgepodge and you have to take time to look up during game play to determine modifier to this or advantage/disadvantage.

Also it would not hurt to have a catchy little phrase for the mechanic that is not as long winded as advantage/disadvantage.

 

[Ichneumon]

Also it would not hurt to have a catchy little phrase for the mechanic that is not as long winded as advantage/disadvantage.

AV/DV ?