D&D 5E Encounter/CR Rules An Artform

[Oofta]

Threads like this make me remember how much I miss the 4e monster math.

I find it odd that people have such difficulty. Once I found the alternative spreadsheet (similar to the guide in XGTE) it's worked pretty well.

It takes a bit of trial and error to figure out what works because every group is different, but once I dialed it in it's been quite accurate. Then again I tend to have 5-10 encounters between long rest, people rarely have much prep time and I use environment and tactics to the monster's benefit.

But even if the group stomped on all the encounters it would just mean I need to up my XP budget.

 

[DEFCON 1]

My inclination is to say the Challenge Rating and encounter building rules have been set up to be relatively balanced only against a 4-person party using the Basic Rules. Basically a new-player game.

Thus probably only one character to heal others, one character to put out AoE with any possible consistency, no feats, many fewer classes that reduce the possibility of good class synergy, and many fewer PCs to reduce the number of hit points and actions to be taken in a round.

You change any of these things and the power of the party begins growing exponentially. More PCs means maintaining steady damage against monsters even when some are using action to heal others. More PCs on their feet means more hit points for monster to have to churn their way through and less actions available to do so against them. More varied classes and using feats means more opportunities for mixing and matching powers and features and spells together to maximize effectiveness-- gaining more opportunities for Advantage, more AoE damage, more blockers and defenders to keep enemies away from the PCs in the back lines.

Has anyone actually ever run a new-player-friendly Basic Rules game with only 4 PCs? And did you design encounters using CR and the builder rules? If so, did they actually work as-is or did you still have to fuzt with it?

 

[Celebrim]

I think CR has been a step forward from the much vaguer situations in 1e or 2e, but it should not be treated as a hard and fast rule. In other words, I fully agree with you that producing fair and interesting challenges still remains more of an art than a science.

The following always remains true:

1) CR is often wrong. Assigning CR in the first place is an artform, and it's often wrong in published material by +/-1 or in some cases even +/-2.

2) Even when CR is not wrong, the range covered by a single CR is fairly large. If you take any arbitrary number, say CR 5, you will be able to find some monsters that are CR 5 which are almost but not quite CR 4 and others which are almost but not quite CR 6. That means within the same CR range you can have monsters which are 150% or more as deadly as other monsters with the same CR. Similarly, if you are RBDM, you know that you can make small tweaks to a monster that are insufficient to alter it's CR but which make it 10% or 20% more effective. A good example is a default Ogre has primitive weapons like a club and makeshift hide armor. But an ogre working as a mercenary might have a two-handed sword and mail. That change makes the Ogre much more dangerous, but not so much more dangerous that it bumps it up a full CR.

3) Every campaign and every party is different in its assumptions and in its composition, and as such different challenges will be of different difficulty to different groups. Some parties I've had were tightly focused on melee combat, and anything that they could close with and surround would get beat down quickly. Other parties I've had focused on battlefield control and ranged combat, and anything that couldn't close quickly with them would be easily dispatched. Those two parties will have very different challenges with a burrowing ambush predator that achieves surprise. Likewise, I've had a party focused on undead slaying that could handle masses of undead that would have been lethal to a different party composition of the same level.

4) CR never takes into account tactics. In particular, the terrain that a fight takes place in massively alters the effective CR of something. If the monster is fighting in its favored terrain and circumstances, it will tend to be massively more dangerous than when it is not. As a very simple even comical example, a giant shark is a very different encounter when encountered on land, encountered in a boat, and encountered when the party is in the drink with it. The effective CR of a monster depends a lot on the lair the DM designs for that monster, and double or half the encounter difficulty all by itself. Any lair that the monster can make better use of than the party is a massive advantage that should be accounted for but often isn't. Coming from the opposite direction, challenge rating almost always assumes that the party will adopt the most effective tactics to counter and defeat a monster. But if the party doesn't understand the weakness of what they are facing or adopts the wrong strategy, the challenge can go up enormously. That party that is good at surrounding things and beat them down, if they adopt that strategy against a monster whose CR is based on the assumption the monster can and should be kited, will massively up the lethality of the monster.

5) CR never takes into account synergy. Synergy happens when two monsters are more than the sum of their parts, because each is able to cover for the others weakness. For example, a troll and spellcaster working together are more dangerous than either alone, because the spellcaster can give the troll resistance to fire while the troll can tank for the spellcaster and use it's reach to provide battlefield control. Synergy also happens when you alter an existing monster in a way that the rules for altering a monster consider to normally be minor, but which in this particular case cover up for a monsters weakness tremendously. An example might be a small or medium sized grappler tends to have low CR on account of the weakness of its main attack - grappling. Normally increasing a monster by a size category has only a minor increase in its effective CR, but increasing a small or medium sized grappler by a size category tends to have synergy and increases CR by more than the normal degree.

 

[Celebrim]

Threads like this make me remember how much I miss the 4e monster math.

4e went all in on making encounters be balanced and predictable, and yet it has many of the same problems.

4e math assumes that the party will be balanced and equally divided between the 4 interchangeable party roles.

4e math assumes that the encounter will take place in a relatively small "arena" which is at a scale wherein the powers and move capabilities of both sides are highlighted.

And so forth. And that's to not even get to the fact that the initial math that they used generated monsters that were generally too weak at higher levels to seriously threaten a compotent and well built PC party.

 

[Oofta]

Another quick note on CR: the original monster manual was released before the DMG and the final rules for how to determine CR were still being finalized. I find that monsters created after the DMG was created are a little closer.

However, there is still no way that CR will ever be more than a general guideline. One group may have high overall ACs but poor dexterity saves for example. So those hell hounds, whose CR is based in large part on their breath weapons, will be more effective against some groups than others. Doubly so if the group has time to prep.

I remember way back when having a conversation with one of the WOTC devs working on 3E* how hard it was as a DM building encounters or custom monsters for 2E. No real guidelines, just take a gander at the monsters and hope for the best. No guidelines for XP for custom monsters. I had my own crude guidelines taking into consideration damage, AC, HP but nothing as comprehensive as what we had now. Most of the time we just winged it.

Which is all to say the current guidelines are far from perfect, but I find they still work fairly well. I still have to take into consideration a bunch of variables that can't be put into a spreadsheet. D&D isn't a board game with identical pieces, it's the best we can hope for.

*My brother-in-law lives in Seattle and he won a charity contest to play with a dev at WOTC HQ not that long after they'd bought TSR. It was quite fun even though my PC died a valiant death.

 

[5ekyu]

It has seemed to me that the CR DMG was scaled for the assumption of "relative novice of systrm" and " low to average tactical savvy" with a lot of wiggle room. Thst seems good to me to prevent the slaughtered-newbie-walks before they get a handle on things.

For groups who know enough to optimize, to use savvy tactics etc its expected the GM knows to adjust.

BTW what are golks views on the XGtE alternative encounter balancing?

 

[tetrasodium]

It has seemed to me that the CR DMG was scaled for the assumption of "relative novice of systrm" and " low to average tactical savvy" with a lot of wiggle room. Thst seems good to me to prevent the slaughtered-newbie-walks before they get a handle on things.

For groups who know enough to optimize, to use savvy tactics etc its expected the GM knows to adjust.

BTW what are golks views on the XGtE alternative encounter balancing?

the xge charts are a pretty decent ballpark tool, the game being "balanced" around a style of play nobody uses is probably a big part of why the dmg calculations are kinda useless compared to prior editions, Celebrim touched on that style above

 

[robus]

As @Quickleaf notes, the CR is only relevant if the PCs are going to be sufficiently challenged over the course of an adventuring day. If they can nova the only encounter of the day then yeah, unless the monster gets some lucky rolls/high initiative it's not going to provide a sufficient challenge. Now that my players are at level 19 I've completely thrown out the guidelines and just throw whatever seems thematically appropriate for the adventure at hand - But I'll generally boost monsters with attack bonuses (if they seem low) and more HP to make the fight more challenging.

Someone also had the great suggestion of forgoing initiative rolls for monsters, just use a fixed initiative: dumb monsters 10, smart monsters 15 and bosses 20 (given that I rolled a 2 for some monsters initiative - in a low level game - I'm especially partial to this idea )

As for the tables in Xanathar's guide, I think they're great for low level encounter planning.

 

[Tony Vargas]

I think CR has been a step forward from the much vaguer situations in 1e or 2e, but it should not be treated as a hard and fast rule.

That's fair, and very well-chosen, because it is a step forward from those editions. And a lateral move from 3e, and a big step back from 4e.
Which is so frequently the case with everything 5e has done as a Compromise/Big-Tent edition trying to pull the high points from each prior ed, that we really should be used to accepting it, by now, 5 years in.

I mean, 3e introduced CR, and 4e improved on it substantially, but 5e, had to call back the TSR eds, as well. It couldn't make encounter building into a detailed optimization mini-game counter to the players build-optimization mini-game like in 3e, or a neatly-balanced exercise in set-piece combat 'scene' choreography like 4e. It had to bring us some of the uncertainty and DM/player 'skill' of the olden days, too.

In other words, I fully agree with you that producing fair and interesting challenges still remains more of an art than a science.

It is, indeed, once a gain, primarily an art - a matter of feel, experience, improvisation, and creativity. Which is both a good deal of fun, and takes a good deal of skill/talent/energy to get the most of out of.

So, yes, the following are, once again, true, and advisedly/intentionally so:

1) CR is often wrong. Assigning CR in the first place is an artform, and it's often wrong in published material by +/-1 or in some cases even +/-2.

'Wrong' is the er, wrong? word for it. YYMV, maybe? CRs in published materials seem to follow a formula, that formula, thanks to BA, doesn't stand up to the linear-distribution randomness of the d20, nor party composition nor optimization, since balance on the player side is also far more varied for similar reasons.

2) Even when CR is not wrong, the range covered by a single CR is fairly large.

It maps to level, still. While BA means a party can functionally engage CRs far above and below them, it's still centered around a lone same-CR critter as a meaningful little challenge.

3) Every campaign and every party is different in its assumptions and in its composition, and as such different challenges will be of different difficulty to different groups.

Yes choice of class, build choices, pacing, and many other factors radically distort balance among classes and vs encounters. It's inevitable given the mandates of 5e design. You simply can't give some classed no meaningful daily resources, and others game-changing ones, and give players any freedom in the 'length' of their day and expect any set of encounter guidelines to hold up!

4) CR never takes into account tactics. In particular, the terrain that a fight takes place in massively alters the effective CR of something.

Well, it can, if the DM sets it up that way and runs to that level of granularity.
In this case, though, I think 5e CR deserves a free pass: the game assumes TotM, TotM doesn't support highly granular tactics.

5) CR never takes into account synergy. Synergy happens when two monsters are more than the sum of their parts, because each is able to cover for the others weakness. For example, a troll and spellcaster working together are more dangerous than either alone, because the spellcaster can give the troll resistance to fire while the troll can tank for the spellcaster and use it's reach to provide battlefield control.

And it exists on the players' side of the screen, too!

 

[Celebrim]

@Tony Vargas : There seems to be some 4e partisanship going on in your response that makes a ton of assumptions.

For example, with respect to Theater of the Mind, most of the 1e/2e play that I did used TotM as well, but that didn't prevent terrain from having a big impact on the combat situation. Consider just as one of many examples, the terrain challenges poised by a module like S2: White Plume Mountain. Even if 1e didn't have a unified terrain and skill mechanics, terrain minigames specific to an encounter were common in 1e play even in situations where TotM play was assumed. I mean seriously, you wouldn't expect a 1e table accustomed to assume TotM play to nonetheless assume combat continued to function as normal if a Paladin in platemail fell into the salty sea while battling a squid. There would be certainly assumptions made about the ability of the Paladin to move in this new environment - to say nothing of breathing in it. Things like the spell 'Darkness' or just fighting at night creates terrain in 1e even if you are playing in 1e TotM. So I don't think you can say that because 5e assumes TotM that terrain doesn't have a big impact on combat and challenge within it.

As for the assignment of CR, 3e, Pathfinder, and 4e all had monsters which were notorious for being harder than their CR suggested, and which had they been published at the next higher CR probably wouldn't have caused much remark. And as far as I can tell as an outsider, 5e has continued this with several monsters being much harder than their CR would suggest - ropers, magmin, intellect devourers, shadows, zombies, etc. So when I say that the CR is wrong, I mean 'wrong' in a very literal sense that the wrong number was probably assigned to the CR. I mean that even given that all the system expectations were met, the monster in question not only on average outperforms the normal expected amount of party resources consumed, but actually usually forced the expenditure of the sort of resources expected by the next higher CR.