D&D 5E DMG's definition of "Deadly" is much less deadly than mine: Data Aggregation?

[intermedial]

Absolutely. The three round rule is just a conceit, based on the DMG's recommendation to use that as a baseline for building your own monsters. If you could create a simulation tool as Hemlock recommends, it would be far more accurate. If fact, you could even have that tool account for how long you want the encounter to last, and how many other encounters the party may face.

It might not account for all the nuances of combat, but it'll give you a good general approximation.

That said, after three rounds, many monsters start to run out of interesting things to do anyways. Furthermore, based on the size, experience, and level of your party, three rounds might be an appropriate place to move on depending on the pacing of your session. It's a good, solid assumption, and building your encounters around a three-round structure carries several benefits with regard to encounter balance, narrative structure, and overall session pacing.

Obviously, climatic battles warrant more rounds, so that's easily remedied (you can adjust HP and DPR to result in a longer or shorter combat).

 

[Mark CMG]

Aren't you a tyrant DM who wants to slaughter your PCs with Deadly encounters, Quickleaf?

This, among other things, got my morning started. Thanks.

 

[Rhenny]

Talking about rounds, I think that because 5e was designed to play more quickly than previous editions, in general, fights will not last as long (of course, when you pile on the monsters that's a different story). As a result, shorter combats tend to have more variance and unexpected results. One of the reasons why 4e monster math was probably the most exacting and predictive was because combats tended to take longer as 2nd wind, more hit points and other factors prolonged the battles. This is neither good nor bad, just different.

Personally, I like being surprised by the results of an encounter, even as a DM. It kind of keeps me in the game.

 

[Quickleaf]

One thing I think is interesting is the question of expectations: What is "hard" or "deadly" for a given group? With some groups I played with back in my AD&D days, an encounter wasn't "hard" unless they were scrounging for wealth to pay for a resurrection spell for someone afterward, while in my current set of campaigns (where half the players never played pre-WotC D&D and the investment is primarily in the characters and story rather than the game mechanics while still seeking a fun challenge) an encounter is "hard" if anyone worries their character will drop to 0 and "deadly" on the first death save failed.
Those are really, really huge differences.

Sure, some groups want death as a consequence and other groups do not.

However, this shouldn't affect the difficulty of encounter design.

Instead, it should affect how the DM interprets failure in combat (or a failed "death" save). It could mean capture, it could mean the enemy accomplishes a horrible ritual, it could mean X, Y, and Z. "Death" is simply an agreed upon narrative consequence. A group can decide to remove or minimize that consequence. But that doesn't change the maths behind what is an Easy/Medium/Hard/Deadly difficulty encounter.

Well, I had my first session of "official" (as opposed to playtest) 5e tonight. And...well, from my experience there, the difference between Hard and Deadly is very difficult to see. Our DM had us starting at first level...and holy crap was the fight a meat-grinder.

1st level is notoriously deadly in 5th edition, so don't think that it is indicative of how the rest of the game plays at higher levels. Even at 2nd level I've see our party have greatly improved survival. 1st level is an anomaly.

 

[UngeheuerLich]

If you're going granular, why not go full-bore and use actual simulation tools? You'll get even more granular results. Just as the easiest way to figure out how often Lore Bards can Counterspell Meteorswarm (d20-at-advantage +d12 Peerless Skill +8 for Jack of All Trades) is not to use a mathematical formula but instead to just do the rolls a thousand times (it's a 77% success rate BTW), the easiest way to figure out how difficult a given combat will be against N PCs with capability X is to actually simulate that combat a few thousand times with some simplifying assumptions.

On the other hand, if you try to break things down into a bunch of complicated statistics that you have to manually apply to each other, you wind up with the worst of both worlds.

It shouldn't be too hard to whip up a little tool that lets you set up HP and single vs. AoE attacks (AC- or save-based) on two sides of a combat and then predicts how many HP each will have lost at the end of the combat in the form of a probability distribution (NOT just a mean). Then all you need is a good metric for assigning labels, e.g. "if the PCs end the combat at zero HP more than 1% of the time, it's Deadly; if they usually end it at 90% of HP, it's Easy; if they end at 80%, it's Medium; otherwise it's Hard."

This is kind of like intermedial's approach except without the simplifying assumptions like a three-round combat, which IMO are too simplistic.

Nah. Too complicated. And honestly... i am fine with what we have. But OCR and DCR and maybe OCR splitted into range and melee and we have a very good approximation.

I don't need those ratings, because I am quite good with numbers and I actually don't care about balance... but new dms could profit from such numbers

 

[aramis erak]

IME, a "Deadly" fight is one that I can count upon to drop a PC if I pick on a single target.
At twice the deadly, I can figure half of my PC's will be KO'd.

 

[FormerlyHemlock]

Absolutely. The three round rule is just a conceit, based on the DMG's recommendation to use that as a baseline for building your own monsters. If you could create a simulation tool as Hemlock recommends, it would be far more accurate. If fact, you could even have that tool account for how long you want the encounter to last, and how many other encounters the party may face.

It's on my mind partly because I am building something to use for running simulations/automating combats. I'm currently sidetracked on parsing issues and learning how to write a packrat grammar, but if you want to go to http://maxwilson.github.io/RollWeb/Roll/ and ask it what "d20-d20+7" is or what is the average "avg.3d8+1d6-2", it can tell you. Obviously it's not anywhere near ready to tell you how much damage three 5th level fighters will take against three ogres but that is a direction I'm interested in.

However, in order to turn that into some kind of Deadly/Hard/Medium rating, you'd need to have some idea of what those words mean. Is a fight with a 1% chance of at least one PC dying Deadly, or Hard? Is it still Deadly if the dead PC can be Revivified? What makes a fight Easy? Is a fight where Hypnotic Pattern turns a 30% chance of TPK into 0% chance of TPK Deadly or Medium? Things like that.

 

[FormerlyHemlock]

1st level is notoriously deadly in 5th edition, so don't think that it is indicative of how the rest of the game plays at higher levels. Even at 2nd level I've see our party have greatly improved survival. 1st level is an anomaly.

It's a fun anomaly though.

Doing Out of the Abyss right now and I'm finding that 2nd level can still be quite dangerous if you don't even have 1st level equipment (chain mail, shields, bows, etc.). Chain shirts are... not great. Especially for a PC with Heavy Armor Master.

 

[GX.Sigma]

So far, no encounters have felt deadly in 5e--except for ones that felt unfair, like a CR+10 monster with breath damage 3x the characters' max HP, or five wraiths coming out of a wall behind you and hitting you with surprise life drain.

I think a big part of the problem is the labels of the difficulty levels. "Easy, Medium, or Hard" is not doing it for me. It implies the PCs are supposed to win each encounter, and the DM just has to figure out how much of an inconvenience it's going to be. In this system, it's hard to make sense of the "Deadly" label.

I'd rather have thresholds like this: Speedbump (e.g., Batman vs. some random thugs), PCs Favored (e.g. Batman vs. Joker), Evenly Matched (e.g., Obi-Wan vs Anakin in Episode III), Opponents Favored (e.g., Obi-Wan vs. Darth Vader in Episode IV), certain death (e.g., the Hobbits vs. the Nazgûl), and "are you crazy?" (e.g., Frodo vs. Sauron). Those would be more helpful descriptors, especially since I want to run a world where some enemies are supposed to be totally out of the PCs' league.

The problem with any mathematical system for encounter difficulty is that different groups will have different amounts of treasure, system mastery, and tactics. Thus, whatever math you're using, you'll have to re-calibrate it for each individual PC group. Perhaps with some sort of danger room.

But honestly, the only actual way to see how the encounter is balanced is to playtest it and see how it goes. Dicking around with numbers can only get you so far.

 

[FormerlyHemlock]

Talking about rounds, I think that because 5e was designed to play more quickly than previous editions, in general, fights will not last as long (of course, when you pile on the monsters that's a different story). As a result, shorter combats tend to have more variance and unexpected results. One of the reasons why 4e monster math was probably the most exacting and predictive was because combats tended to take longer as 2nd wind, more hit points and other factors prolonged the battles. This is neither good nor bad, just different.

I just don't get the mentality of "longer combats are more deadly." Say you're fighting a Duergar Xarrorn from OotA. Or actually, let's say you and your buddies are 5th level, and there are four Xarrorns (CR 2). Let's now say each of the Xarrons Enlarges itself so that it can get 2d12+d6+3 damage on its attacks instead of just d12+d6+3. You can either: 1.) engage it while it is Enlarged, suffering 50% more damage for no good reason, or 2.) fall back for the next 60 seconds until they shrink down to normal size, negating their advantage (because their puny 25' movement cannot keep up with even a normal human's ability to Disengage and move 30').

Option #2 makes the fight take e.g. 13 rounds instead of 3 rounds, but it is clearly safer.

What makes a combat deadlier has more to do with the number of decision points and critical events in it than it does with the duration.