D&D 5E CR and Encounter Difficulty: Is It Consistently Wrong?

[I'm A Banana]

This is just theorycraft for me, but 6 Hobgoblins seems like an extremely challenging battle for a 1st-level party, one that will likely drain almost all of their resources. Isn't that what people are asking for?

A fight with 6 hobgoblins would likely challenge the party too much, because they'd be missing the two short rests that the daily XP total presumes when it's figuring what is "reasonable" - so they're likely to run out of healing and nova effects before they should. The DMG/Basic goes into this a bit in the "Multipart Encounter" section

But other than "have one hobgoblin encounter that comes in 3 waves of 2 hobgoblins each with 1 hour between the waves for a short rest" (which, at the very least, is REALLY artificial), there's no easy way to have one big encounter in each day that actually eats up a day's worth of resources without killing the party.

It's possible -- the easiest way to do it is just to introduce ways that PC's can spend HD to heal HP, like a healing rune circle or a Second Wind action -- but the DMG doesn't talk much about how to actually pull that off.

 

[Mistwell]

Dude. Turn down the shrieking

Sorry it was four in a row, and I took all four out on you...didn't mean to do that.

and review the table on page 275 of the DMG.

That is, once again, rules for making a new monster. NOT THE RULES FOR ENCOUNTER BUILDING. Those are different, optional rules that not in any way the topic we're talking about. Heck it's not even the primary section of those optional rules, you're using a chart from the "Creating Quick Monster Stats" sub-section to be used when you don't have time to do it the right way. That chart is absolutely not intended to be used the way you're using it, to judge entire encounter difficulty.

There is an entire long section of the DMG on the topic we're talking about, starting on page 81 of the DMG, and the new monster building rules are not them. Why don't you want to use them? Particularly since you think the system you're using (which is never mentioned in the encounter difficulty topic of the DMG to begin with) isn't working well for you (no surprise there). Don't you think it might be wise to check out the section of the DMG meant for that topic?

It could well be the new monster building rules don't work well, but why on earth would you reference them on this topic? When talking about whether or not the encounter building rules work well or not - the encounter building rules don't use CR, and are not related to the optional new monster building rules in a different part of the book.

There is one non-optional tool used to judge Encounter Difficulty in the DMG, and that is XP, with the one exception of that warning light issue I mentioned. That's the core rule.

 

[FormerlyHemlock]

When four people in a row make the same mistake at some point it becomes irritating that they're not listening.

That is, once again, rules for making a new monster. NOT THE RULES FOR ENCOUNTER BUILDING. Those are different, optional rules that not in any way the topic we're talking about. There is an entire long section of the DMG on the topic we're talking about, starting on page 81 of the DMG, and the new monster building rules are not them.

It could well be the new monster building rules don't work well, but why on earth would you reference them on this topic? When talking about whether or not the encounter building rules work well or not - the encounter building rules don't use CR, and are not related to the optional new monster building rules in a different part of the book.

There is one non-optional tool used to judge Encounter Difficulty in the DMG, and that is XP, with the one exception of that warning light issue I mentioned. That's the core rule.

If "four people in a row" make the same "mistake" by referencing something something that is "not in any way what we are talking about," then it is just possible that "we" are not talking about what you think we are talking about.

Since my first post in this thread I've been discussing primarily monster-building, and only secondarily about encounter-building (which is derived from monster-building). Here's a quote:

Neither consistent nor unpredictable. I can eyeball a monster and say, "That CR monster is a pushover: since it has only 30 movement, Int 1, and no stealth abilities, a smart party can just disengage and kill it from range." Then I look at orcs and say, "Due to the Aggressive trait, CR is pretty accurate; if the party gets advantage via ambush or similar, they can handle large numbers of orcs, but in a white room scenario the orc's full HP/damage will come into play and it will be as deadly as CR implies." Then I look at Intellect Devourers and say, "Can possess humanoid hosts to attack from stealth; deals perma-stun on an Int save with a special condition on top; can auto-kill anybody who is asleep and take over their body; this guy is wildly and crazily dangerous even to 10th level parties, although variance on the outcomes will be high."

The main thing that keeps a monster from being very deadly is a low Int score, because then it won't use tactics. Therefore, an Iron Golem in an abandoned tomb is a pushover, but an Iron Golem under the active direction of the artificer who created him is a credible threat.

So we are, in fact, talking about monster building. If you're confused why your repeated citations of the encounter building rules aren't shutting down discussion, that's why.

Well, that and the fact that you're way too hung up on the idea that XP and CR are supposedly independent quantities instead of a functional bijection. If you could cite some examples of monsters whose CRs don't match their XP values that would be interesting.

 

[Fanaelialae]

Hmmm this is weird. If the encounter is more difficult because of larger than usual numbers of foes, why doesnt that translate into xp the party is awarded? Makes no sense to me.

I believe it's because the designers wanted to encourage strategic play.

If larger encounters = more xp, players are encouraged to take them head on.

On the other hand, if the xp works as is, smart players will divide and conquer when possible. If you know there are a lot of orcs in a room and you figure a way to lure them out in smaller groups and ambush them, then you've earned the same xp for far less risk and resources.

That's my take on it anyway. If you were to award the players xp equal to the actual difficulty of an encounter, I don't think there'd anything wrong or game breaking about it. You'd simply be encouraging them to take a more direct approach.

 

[Psikerlord#]

I believe it's because the designers wanted to encourage strategic play.

If larger encounters = more xp, players are encouraged to take them head on.

On the other hand, if the xp works as is, smart players will divide and conquer when possible. If you know there are a lot of orcs in a room and you figure a way to lure them out in smaller groups and ambush them, then you've earned the same xp for far less risk and resources.

That's my take on it anyway. If you were to award the players xp equal to the actual difficulty of an encounter, I don't think there'd anything wrong or game breaking about it. You'd simply be encouraging them to take a more direct approach.

Yeah I can kinda understand that. Although the incentive to divide and conquer is already there even without xp taken into account (it's just easier to win if you split the enemy group into smaller pieces at a time). I think I will experiment with awarding adjusted xp from now on. I prefer a quicker advancement anyway.

 

[Jaelommiss]

I think the primary reason that Mistwell is unwilling to accept using CR for encounter building is because the encounter building rules are entirely incompatible with CR. There is no way that I can see to modify the XP budgets to accomodate using CR.

Yes, XP values are based on the CR of the monster. However, there is no reliable equation for determining a creature's XP from CR or vice versa. We need to use a chart that uses arbitrarily determined equivalents because there is no mathematical way to convert one value to the other. If CR could be used to determine encounter budgets, then we could deduce this equation, and it would fit the available data perfectly (R² = 1).

I decided to try creating an equation to convert CR to XP by plotting the values for both and setting linear and polynomial trendlines of second and third orders. Any equation that could be used for converting CR to XP must a) be a very near perfect representation of the CR to XP table (R² > 0.99), and b) have no significant anomalies.



Let's take a look at the equations we get, shall we.

The first one is a simple linear equation that correlates extremely loosely with the available data. With an R² value of 0.7148 it is safe to say that it is entirely nonrepresentative of the CR/XP charts.

The next one, a second order polynomial equation, is far closer to the values given by the CR/XP charts. With an R² of 0.9598 it is far closer to the data we have available. But look at the lower end of the CR scale, specifically between zero and twelve. If this equation is correct, extremely low CR creatures grant over 7000 XP, while CR 3-12 creatures grant negative experience. This would count as a significant anomaly.

Finally we have the third order polynomial. This equation is extremely close to the CR/XP tables (R² = 0.9971), and has no glaring errors at a glance. However, consider the complexity of the equation. I have serious doubts that WotC decided upon the equation y = 13.801x³ - 324.34x² + 2544.1x - 1770.8 to determine the XP for a given CR. It is highly unlikely that anyone would suggest such a lengthy and unwieldy equation is used for a version of D&D that emphasizes simplicity to such a great extent. It also gives negative experience for CRs below 1.

Because there is no clear and reasonable correlation between CR and XP values (at least not with the charts provided), it is unreasonable to assume that CR can be substituted for XP when using the encounter difficulty charts or that the two are closely linked.


If anyone has a simpler way to prove a relation between CR and XP, by all means show me. Being able to use CR to create balanced encounters would be far simpler than adding and multiplying XP values for several monsters. It's just that I cannot see that link, and thus dissociate the two.

Of course, this entire concept breaks down when you realize that XP, CR, and encounter difficulty are all more or less eyeballed in the first place...

 

[FormerlyHemlock]

Because there is no clear and reasonable correlation between CR and XP values (at least not with the charts provided), it is unreasonable to assume that CR can be substituted for XP when using the encounter difficulty charts or that the two are closely linked.

If anyone has a simpler way to prove a relation between CR and XP, by all means show me. Being able to use CR to create balanced encounters would be far simpler than adding and multiplying XP values for several monsters. It's just that I cannot see that link, and thus dissociate the two.

There's a bijection between CR and XP value, as you must be aware. How is that not a relation? All functional relations are relations by definition. I don't know of a closed-form continuous solution that would let you transform the encounter-building guidelines into simple CR-based guidelines instead of XP-based guidelines[1], but why would you want that? Nobody that I know of is suggesting throwing out the XP guidelines at all, they're just using the term "CR" loosely. The key observation was made by Pickles JG:

Anyway I think that people are using "CR" loosely to mean "encounter balancing" guidelines. Whether that is because the CRs are wrong or the budgets are wrong is interesting but not needed to say whether the system as a whole works.

So, this whole CR vs. XP discussion is a tangent, a distinction without a difference.

In any case, Jaelomiss, I agree with your closing statement: encounter difficulty is best more or less eyeballed. (And kill XP is an anachronism which has potentially corrosive effects on the game.)

[1] Or equivalently, CR-based guidelines which calculate XP from CR as an intermediate step.

 

[DaveDash]

I think the primary reason that Mistwell is unwilling to accept using CR for encounter building is because the encounter building rules are entirely incompatible with CR. There is no way that I can see to modify the XP budgets to accomodate using CR.

Yes, XP values are based on the CR of the monster. However, there is no reliable equation for determining a creature's XP from CR or vice versa. We need to use a chart that uses arbitrarily determined equivalents because there is no mathematical way to convert one value to the other. If CR could be used to determine encounter budgets, then we could deduce this equation, and it would fit the available data perfectly (R² = 1).

I decided to try creating an equation to convert CR to XP by plotting the values for both and setting linear and polynomial trendlines of second and third orders. Any equation that could be used for converting CR to XP must a) be a very near perfect representation of the CR to XP table (R² > 0.99), and b) have no significant anomalies.



Let's take a look at the equations we get, shall we.

The first one is a simple linear equation that correlates extremely loosely with the available data. With an R² value of 0.7148 it is safe to say that it is entirely nonrepresentative of the CR/XP charts.

The next one, a second order polynomial equation, is far closer to the values given by the CR/XP charts. With an R² of 0.9598 it is far closer to the data we have available. But look at the lower end of the CR scale, specifically between zero and twelve. If this equation is correct, extremely low CR creatures grant over 7000 XP, while CR 3-12 creatures grant negative experience. This would count as a significant anomaly.

Finally we have the third order polynomial. This equation is extremely close to the CR/XP tables (R² = 0.9971), and has no glaring errors at a glance. However, consider the complexity of the equation. I have serious doubts that WotC decided upon the equation y = 13.801x³ - 324.34x² + 2544.1x - 1770.8 to determine the XP for a given CR. It is highly unlikely that anyone would suggest such a lengthy and unwieldy equation is used for a version of D&D that emphasizes simplicity to such a great extent. It also gives negative experience for CRs below 1.

Because there is no clear and reasonable correlation between CR and XP values (at least not with the charts provided), it is unreasonable to assume that CR can be substituted for XP when using the encounter difficulty charts or that the two are closely linked.


If anyone has a simpler way to prove a relation between CR and XP, by all means show me. Being able to use CR to create balanced encounters would be far simpler than adding and multiplying XP values for several monsters. It's just that I cannot see that link, and thus dissociate the two.

Of course, this entire concept breaks down when you realize that XP, CR, and encounter difficulty are all more or less eyeballed in the first place...

There is no formula that represents level based on XP either, but there is certainly a relationship between XP and leveling.

 

[DaveDash]

Building monsters is not building encounters. The question posed in this thread was encounters, not individual creature design.



False. The system is not based on CR. The system is based on XP. They say that outright - it's not really open to interpretation, the entire encounter building section uses XP and only XP.



Only for building new creatures/NPCs. But most games are not doing that...those are in fact all optional rules to begin with. There is an entire book of monsters/NPCs to use, and it's intended to be used for just that.

Encounter difficulty is derived from XP which is derived from CR. Fact.

A huge portion of the game is building NPCs, modifying monsters, and building new creatures. I'm running a City of the Spider Queen conversion and it is stacked full of custom monsters and NPCs. Heck there are something like 40 pages worth of NPC stat blocks, most of them combat NPCs.

If the system is based on XP and not CR, where are the guidelines on how to create all those NPCs based on XP only?

The DMG itself refers to the NPCs in the monsters manual as 'templates' to be modified for your own games, otherwise you would have no NPCs to use mid to high levels, the core rules (Conjure Elementals) *require* you to adjust monsters based on their CR and the spell level used, and huge swaths of summoning spells in the game function upon CR.

CR *IS* the primary factor for determining a monsters lethality in the game, and it *IS* directly related to building encounter guidelines. Just like levelling is the primary indicator of PC power, and it is directly related to experience as well.

 

[Mephistopheles]

In any case, Jaelomiss, I agree with your closing statement: encounter difficulty is best more or less eyeballed. (And kill XP is an anachronism which has potentially corrosive effects on the game.)

This is the conclusion I'm drawing from this discussion.

Seems like the sidebar on Challenge Rating (DMG, p. 82) may contain the best advice in the encounter building section: look at monster statistics and abilities, gauge them against your PCs (and players, I'd add), use your judgement. Same as it ever was (prior to 3E, that is).