D&D 5E Fixing Challenge Rating

[Zardnaar]

By the way, just so people don’t have to look it up, the Lazy Encounter Benchmark is as follows:

An encounter may be deadly if the sum total of monster CRs is greater than one quarter the sum of total character levels, or half the sum of character levels if the characters are 5th level or above.

For powerful characters above 10th level, an encounter may be deadly if the sum of monster CRs is greater than three quarters of the sum of character levels, or equal to the sum of character levels if the characters are 17th level or above.

A single monster may prove too challenging if it’s CR is greater than the average character level or 1.5. x the average character level if the characters are 5th level or above.

Hmm I've had PCs blow through deadlyX5 encounters which would destroy this.

CR ratings on critters aren't to accurate.

I think the problem may be attempting to write an effective CR/encounter system. It's been 24 years no one's got it right yet.

 

[Stalker0]

I think the problem may be attempting to write an effective CR/encounter system. It's been 24 years no one's got it right yet.

The problem is not creating a system that would accurately represent challenge, I guarrantee you someone could do it. The problem is also making the system simple enough to be easy to use.

the more variables you are willing to add to the system the more accurate it will become....but also the more onerous the system is to use.

 

[tomedunn]

Hmm I've had PCs blow through deadlyX5 encounters which would destroy this.

CR ratings on critters aren't to accurate.

I think the problem may be attempting to write an effective CR/encounter system. It's been 24 years no one's got it right yet.

In my experience helping DMs balance encounters, there are two main reasons for why this happens (maybe one might apply to your case).

Either the DM applied the encounter XP multiplier incorrectly, by including all monsters when determining it, and thus vastly overestimated the adjusted XP for the encounter (this is super common with online encounter calculators, since they always include all monsters). Or PCs were able to set up an effective "kill box" for the encounter, where they could deals large amounts of damage to enemies while those enemies couldn't attack them effectively.

In the first case, the problem is fixable, at least to an extent, through changing the encounter building rules. The encounter XP multiplier shown in the DMG assumes the monsters have similar CR (or more specifically, similar XP values). When that assumption fails to be true it gives increasingly inaccurate results. The alternative rules in XGtE get around this by "recentering" the math around 1 monster / PC, rather than 1 monster / party of 4 PCs.

In the second, I don't think the problem is fixable from an encounter building rules perspective. The fundamental assumption around encounter balancing is that the PCs and the monsters can meaningfully interact with each other during the encounter. If the PCs manage to get themselves in a position where they break that symmetry then all of the math used in encounter balancing goes out the window. I think the best the rules can do in this case is to be clear on what their core assumptions are and when they break down.

I'd also like to point out, for the first case, there's a good mathematical check a DM can make to see if they've likely applied the encounter multiplier incorrectly. You can estimate the maximum possible difficulty of an encounter by taking the square root of every monster's XP, add them up, and then square the resulting total. This represents, roughly, how much XP an encounter would be worth if the PCs distributed their damage evenly across all combatants, waiting to the very last moment before killing them all at once (an extremely sub-optimal tactic). If the adjusted XP total for the encounter ever exceeds this value, something's gone wrong with the encounter's XP multiplier.

 

[mearls]

That said, I’m really interested to see what Mike M. comes up with and I’m so happy to see the value of the work we did in Forge of Foes being used in all new ways.

Thanks man! Forge of Foes has been an invaluable reference. Literally could not do this work without it.

 

[mearls]

Totally agree, leaving it open source is definitely the way to go which GitHub is of course great for. I'm assuming all of your code will be going into the GitHub repo you posted at the top of this thread? I'll make sure to keep an eye out for anything I can help with

Yes, that's the plan. The entire world gets to see my janky code as I hack away at it.

 

[Machiavelli24]

Hey Mike, as someone who tried reverse engineering an encounter building point system, I can warn you away from a pitfall I fell into.

Essentially, increasing a monster by 1 CR makes a monster ~50% more dangerous at low levels but only ~10% more dangerous at high levels (those number values are purely for example purposes). If you cost +1 CR at the same amount every level (like your current system) it tends to result in low level encounters causing TPKs and high level encounters being push overs.

Except it's only noticeable when people build encounters with monsters that are uniformly strong (above the middle point). Which makes it hard to identify this shortcoming in all the noise of people who mix strong and weak monsters together.

The impact of +1 CR is pretty consistent within a tier, so having one price per tier is sufficient. I ultimately (dm me and I'll send you a copy of the two pages) went with one price per level because it let me use memoization to reduce the amount of calculations the end user had to do.

Ultimately, I think one of the most direct ways to improve the experience of CR is to explicitly communicate its assumptions to the end users. For example, CR assumes a giant scorpion will always be making a powerful melee attack, even though an all flying party will effortlessly defeat it. But lowering the monster's CR for not having a ranged attack would result in surprise TPKs against non-flying parties.

 

[Zardnaar]

In my experience helping DMs balance encounters, there are two main reasons for why this happens (maybe one might apply to your case).

Either the DM applied the encounter XP multiplier incorrectly, by including all monsters when determining it, and thus vastly overestimated the adjusted XP for the encounter (this is super common with online encounter calculators, since they always include all monsters). Or PCs were able to set up an effective "kill box" for the encounter, where they could deals large amounts of damage to enemies while those enemies couldn't attack them effectively.

In the first case, the problem is fixable, at least to an extent, through changing the encounter building rules. The encounter XP multiplier shown in the DMG assumes the monsters have similar CR (or more specifically, similar XP values). When that assumption fails to be true it gives increasingly inaccurate results. The alternative rules in XGtE get around this by "recentering" the math around 1 monster / PC, rather than 1 monster / party of 4 PCs.

In the second, I don't think the problem is fixable from an encounter building rules perspective. The fundamental assumption around encounter balancing is that the PCs and the monsters can meaningfully interact with each other during the encounter. If the PCs manage to get themselves in a position where they break that symmetry then all of the math used in encounter balancing goes out the window. I think the best the rules can do in this case is to be clear on what their core assumptions are and when they break down.

I'd also like to point out, for the first case, there's a good mathematical check a DM can make to see if they've likely applied the encounter multiplier incorrectly. You can estimate the maximum possible difficulty of an encounter by taking the square root of every monster's XP, add them up, and then square the resulting total. This represents, roughly, how much XP an encounter would be worth if the PCs distributed their damage evenly across all combatants, waiting to the very last moment before killing them all at once (an extremely sub-optimal tactic). If the adjusted XP total for the encounter ever exceeds this value, something's gone wrong with the encounter's XP multiplier.

Mostly I eyeball it. 1 monster per PC plus a lieutenant type.

If it's an easy encounter I use mooks, medium encounter tougher mods and a hard encounter the CR might be getting close to PC level.

In Cursevof Strahd think we defeated 3 CR5 critters at level 3.

Depends on monsters used, player experience and party composition so there's to many variables.

Still might be able to come up with something for new players. Encounter design isn't hard for me but I couldn't write a formula for it as I eyeball it and tune it towards easy if inexperienced players.

 

[tomedunn]

Mostly I eyeball it. 1 monster per PC plus a lieutenant type.

If it's an easy encounter I use mooks, medium encounter tougher mods and a hard encounter the CR might be getting close to PC level.

In Cursevof Strahd think we defeated 3 CR5 critters at level 3.

Depends on monsters used, player experience and party composition so there's to many variables.

Still might be able to come up with something for new players. Encounter design isn't hard for me but I couldn't write a formula for it as I eyeball it and tune it towards easy if inexperienced players.

Encounters with a group of mooks and one lieutenant can easily come out looking tougher than they actually are for the reason I mentioned. For example, an encounter with 1 x CR 5 (1,800 XP) and 4 x CR 1 (200 XP) against a party of four level 5 PCs will have an XP total of 2,600 XP and an adjusted XP total of 5,200 XP if you count all monsters when determining the XP multiplier, making it a Deadly encounter. That extra 2,600 XP added by the encounter XP multiplier has to come from somewhere.

Since monsters don't generally have their DPR increased significantly when fighting with other monsters, the extra XP needs to come from them living longer, on average, than they would on their own. Twice as long, to be precise. If the PCs can't deal with the CR 1 monsters effectively through AoE abilities then it's possible the CR 5 lives twice as long as it would normally (so around 5-6 rounds), but that would only add 1,800 XP. Similarly, if the PCs focus on the CR 5 first the CR 1s could live twice as long on average, but that would still only add an 800 XP to the encounter.

Neither is enough to justify the adjusted XP total we'd get from counting all monsters when determining the encounter's XP multiplier. And the bigger the relative gap in XP is between the mooks and lieutenant, the more this approach will end up overestimating the difficulty. This is a shame too, since this is a pretty common way people try to build encounters.

 

[Zardnaar]

Encounters with a group of mooks and one lieutenant can easily come out looking tougher than they actually are for the reason I mentioned. For example, an encounter with 1 x CR 5 (1,800 XP) and 4 x CR 1 (200 XP) against a party of four level 5 PCs will have an XP total of 2,600 XP and an adjusted XP total of 5,200 XP if you count all monsters when determining the XP multiplier, making it a Deadly encounter. That extra 2,600 XP added by the encounter XP multiplier has to come from somewhere.

Since monsters don't generally have their DPR increased significantly when fighting with other monsters, the extra XP needs to come from them living longer, on average, than they would on their own. Twice as long, to be precise. If the PCs can't deal with the CR 1 monsters effectively through AoE abilities then it's possible the CR 5 lives twice as long as it would normally (so around 5-6 rounds), but that would only add 1,800 XP. Similarly, if the PCs focus on the CR 5 first the CR 1s could live twice as long on average, but that would still only add an 800 XP to the encounter.

Neither is enough to justify the adjusted XP total we'd get from counting all monsters when determining the encounter's XP multiplier. And the bigger the relative gap in XP is between the mooks and lieutenant, the more this approach will end up overestimating the difficulty. This is a shame too, since this is a pretty common way people try to build encounters.

Well I dont use the guidelines and if it's a tough fight it's CR2-3 per Mook vs 5th level PCs and a CR 5 boss.

CR 1 would be easier encounter.

 

[mearls]

I've updated the system. Digging deeper into the math showed - as many predicted - that the nature of scaling in 5e made this approach a non-starter. Here's a second cut based on an analysis of the math from levels 1 to 20.

5e_point_encounters/challenge_points.md at main · mikemearls/5e_point_encounters

A system for balancing encounters in 5e using point values - mikemearls/5e_point_encounters

github.com