D&D 5E [GUIDE] I Fought the Law and Won: The Rogue Guide

[Yunru]

Why are we assuming that Booming Blade doesn't get the extra damage?
You're a swashbuckler, you run up to the enemy, Booming Blade it, bonus action disengage, retreat.
Either the enemy makes a (probably improvised) ranged attack, or it takes the damage.

One is extra damage, the other is action denial.

TWF (level 5)
Main Hand (base damage): (1d6 + 4) * 0.6 = 4.5
Main Hand (crit damage) : 1d6 * 0.05 = 0.175
Off Hand (base damage) : 1d6 * 0.6 = 2.1
Off Hand (crit damage) : 1d5 * 0.05 = 0.175
Sneak Attack (base) : 3d6 * (1 - 0.4*0.4) = 8.82
Sneak Attack (crit) : 3d6 * (0.05 + 0.4 * 0.05) = 0.735


Total: = 16.51

Counterpoint considering my above statement:

BB (level 5)

Main Attack (base damage)	(1d6+1d8+4)*0.6	7.2
Main Attack (crit damage)	(1d6+1d8)*0.05	0.4
Booming Blade (triggered damage)	2d8*0.6	5.4
Sneak Attack (base damage)	3d6*0.6	6.3
Sneak Attack (crit damage)	3d6*0.05	0.525
	Total	19.825

 

[Blue]

This observation is accurate. There is a way to compute the crit chance to account for this as covered by @Esker.

Assuming the are two attacks, a1 and a2:

critProb(a1|a2) = critProb(a1) + (missProb(a1) * critProb(a2))

If there were three attacks, it would look like this:

critProb(a1|a2|a3) = critProb(a1) + (missProb(a1) * (critProb(a2) + (missProb(a2) * critProb(a3))))


And so on. This math assumes that you will apply your Sneak Attack damage the first time you get a hit, which is pretty accurate based on my experiences.

Also, I stand by my statement that TWF benefits from increased chance to land sneak attacks and to crit with sneak attacks. That is the only reason why it comes out ahead of Booming Blade starting at 5th level. Making multiple attack attacks absolutely increases your chance to land a sneak attack, and it also absolutely increases your chances to land a critical hit with your sneak attack: critProb(a1) + (missProb(a1) * critProb(a2)) is always greater than critProb(a1).

Completely agree more attacks are a great way to have a better chance to land SA. And you are right, your crit change will go up because you can have a miss then a crit, which before would have just been a miss.

The way I read the phrasing had me worried that it was rolling all your attacks, seeing if any were a crit, and then assigning SA to that one. You've since shown that I was in error in that reading, thanks for taking time to respond.

 

[vostygg]

Why are we assuming that Booming Blade doesn't get the extra damage?
You're a swashbuckler, you run up to the enemy, Booming Blade it, bonus action disengage, retreat.
Either the enemy makes a (probably improvised) ranged attack, or it takes the damage.

One is extra damage, the other is action denial.

You are trading more reliable hits and sneak attacks with TWF for situational control/damage with Booming Blade. Ultimately, it's a matter of preference. I've never played in a game where Booming Blade extra damage triggers every round or even most rounds. If I'm lucky, it triggers once per combat. Most rounds, if you happen to hit and your opponent doesn't have a decent ranged attack or isn't next to one of your allies, it provides some action denial. That's fine, if that's your bag. Me, I hate missing, so I prefer the more consistent DPR of TWF. I don't think it's right or accurate to represent Booming Blade as strictly better than TWF, however. People should know that TWF provides higher non-situational DPR for Swashbucklers on average. You can make it even higher with the Dual Wielder feat if you really want to milk it (adds an average of 1.3 DPR per level). This is one of the few cases, other than crit-fishing builds, where TWF makes sense.

 

[Esker]

The way I read the phrasing had me worried that it was rolling all your attacks, seeing if any were a crit, and then assigning SA to that one. You've since shown that I was in error in that reading, thanks for taking time to respond.

You weren't in error; that's exactly what the original table was based on. The qualitative point still stands even with the corrected numbers, but there's still room for disagreement about whether it's reasonable to ignore the rider damage. @Yunru wants to include all of it, @vostygg wants to exclude it.

Seems to me the best measure is somewhere in between. In my experience, movement following a booming blade is rare, and the control effect is often useless, because I've got an ally next to the creature I'm attacking, so the enemy just stays put and attacks them. It's also been my experience that if staying put would really hamper the enemy, they'll move and take the damage rather than accept a tactical disadvantage. But YMMV and all that; it's certainly party, creature, and DM-dependent. In any case, if we want to compare average DPR really accurately, we should try to put a probability on the rider damage taking effect. It's probably pretty low -- maybe 10% or so -- but at some tables it may be substantially higher.

If we do that, we can interpolate between Yunru's numbers and vostygg's. TWF is very likely to come out ahead at lower levels, and BB is likely to come out ahead at higher ones.

But the picture is incomplete even then: TWF has the advantage of being able to do damage to a second creature if the first one goes down (or maybe finish off the first one with your second attack if the first one misses), but BB has the advantage that you can use your bonus action (and your off hand, for that matter) to do something else.

Bottom line, both are reasonable ways to melee-rogue. And thank goodness! Wouldn't D&D be boring if there were only one best way to play a particular class?

 

[vostygg]

The way I read the phrasing had me worried that it was rolling all your attacks, seeing if any were a crit, and then assigning SA to that one. You've since shown that I was in error in that reading, thanks for taking time to respond.

And thank you for your politeness. You were absolutely right to point out the potential flaw in my computations. My original numbers were off in exactly the way you described. Your input and input from @Esker helped me apply the necessary corrections, which appear in my second post. Even with the corrections, however, the non-situational DPR for TWF is higher.

 

[Yunru]

People should know that TWF provides higher non-situational DPR for Swashbucklers on average.

Does it though?
Booming Blade does +3.315 more damage if the extra damage triggers every time that you hit.
The break even point is if you trigger the damage 38.61% of the time (not even factoring in the action denial possibilities).

So unless Booming Blade triggers less than 38.61% of the time, Booming Blade provides higher DPR for Swashbucklers on average.

(I kinda want to work out a build that uses Shield Master to guarantee they'd have to move to make an effective attack.)

 

[Esker]

(I kinda want to work out a build that uses Shield Master to guarantee they'd have to move to make an effective attack.)

Does standing from prone count as movement in terms of triggering the booming blade rider? I would have thought not. Or do you mean shoving away? That could be quite nice if the enemy's turn is between yours and the other melee-ers in the party. Actually it's nice either way; if your melee allies go between you and the enemy, shove prone; if the enemy goes between you and them, shove away.

How about the following:

Half Elf Swashbuckler (taking the High Elf variant for Booming Blade) / Battlemaster

10 STR, 16 DEX, 14 CON, 8 INT, 10 WIS, 16 CHA

Take rogue to 7 first (taking expertise in athletics, obviously), then take the first fighter level, taking defense style, followed by rogue 8-10 for shield master and 20 DEX. Booming Blade now does 3d8 on movement. Then grab a couple more fighter levels, taking riposte, precision attack, and maybe feinting attack for times when you need advantage to proc sneak attack. Take magic initiate (wizard) for an owl familiar, and then maybe elven accuracy to profit further from the help action.

 

[Yunru]

In my experience, movement following a booming blade is rare, and the control effect is often useless, because I've got an ally next to the creature I'm attacking, so the enemy just stays put and attacks them.

Then don't attack that enemy, attack a different one?

It's also been my experience that if staying put would really hamper the enemy, they'll move and take the damage rather than accept a tactical disadvantage.

But that's still more damage for you than TWF then.

Actually it's nice either way; if your melee allies go between you and the enemy, shove prone; if the enemy goes between you and them, shove away.

Yes.

 

[Esker]

Then don't attack that enemy, attack a different one?

I mean, I guess that makes sense if I'm trying to maximize my own DPR, but unless it's a horde of one-hit-killable chumps, it usually makes more sense for the party to focus fire, since injured enemies hit just as hard as uninjured ones (swarm abstractions aside, I suppose). Even if I end up with overkill damage, I'd rather take someone out than not.

 

[Esker]

But that's still more damage for you than TWF then.

Yeah, that's what I'm saying; some fraction of the time, the BB rider actually does go off, so that ought to be taken into account in a DPR calculation. It's small, in my experience -- less than 38% certainly -- but it's there.