CR at Higher Levels or Big Groups, What's Missing?

[DMThac0]

I'm working on some tools that I can use to steamline my job as a DM. I have a spreadsheet for generating random adventures using all the tables from the DMG. I have another one for generating random NPCs and Villains, again using the tables from the DMG. I'm working on a spreadsheet that will allow you to custom build a creature with all the calculations done for you and customize almost every aspect of it. I'm working on a random encounter spreadsheet to handle social, combat, and environment/location encounters for those long treks across the map or whenever. These projects are my way of keeping busy when I'm not in the mood to do real adulting. However, I've found myself asking a question that I'd like some input on and it deals with CR calculation for encounter difficulty and high level and/or large groups:

What information is missing from the CR calculations/Combat Difficulty to help mitigate the apparent dramatic drop in challenge at higher levels or with larger groups? Many of us have found that CR is a good baseline for combat generation but it starts to fall short after a while. We've learned to add strategy, environment and other factors into a combat to make it more challenging to our players. We've got a few buttons and levers we can play with to make a creature more durable or hit harder. The goal here is to give a tool for both the novice and experienced DM that can help calculate a combat encounter much closer to the capabilities of the party they're working with. So, again, what do you feel is missing from a CR calculator that would make the end result more accurate?

[Unoriginal]

CR calculators are accurate for what CR is, and there isn't really something you can change to make it "more accurate". All things like strategy, environment, etc, have nothing to do with CR calculation.


If you wanted to calculate an actual Combat Encounter Difficulty rating, you could do so by calculating how many turns it would take on average for each side to defeat the other, with the conditions for "defeat" depending on what the encounter is.

[PhoenixPhyre]

CR calculators are accurate for what CR is, and there isn't really something you can change to make it "more accurate". All things like strategy, environment, etc, have nothing to do with CR calculation.


If you wanted to calculate an actual Combat Encounter Difficulty rating, you could do so by calculating how many turns it would take on average for each side to defeat the other, with the conditions for "defeat" depending on what the encounter is.

And that's gonna get out of hand very quickly. The parameter space (including interaction terms) is huge.

Really, CR tells the average of two (approximate) things.
* How high of level does a wizard have to be to not be able to be knocked from full to 0 HP in one average round [OR-KO] from the monster (offensive CR X = average damage will OR-KO a 14-CON wizard of level X-1)
* What level of party (assuming Basic Rules, no feats/items/multiclassing) the creature should be able to survive 3 combat rounds under fire from (defensive CR X = 3 rounds vs 4-man-band of level X)

Tactics, terrain, monster synergies are all explicitly out-of-scope for CR while still being part of encounter balance. The presence of feats, multiclassing, and magic items all skew the CR numbers to the easy side.

[DMThac0]

CR calculators are accurate for what CR is, and there isn't really something you can change to make it "more accurate". All things like strategy, environment, etc, have nothing to do with CR calculation.


If you wanted to calculate an actual Combat Encounter Difficulty rating, you could do so by calculating how many turns it would take on average for each side to defeat the other, with the conditions for "defeat" depending on what the encounter is.

Fair points, and yes I'm leaning more toward the second half of what you said. (I'll update the language after this response.)

So, with what you're suggesting, you take "Monster A" vs a party of four and figure that if Monster A has 86 HP and the party can dish out an average of 26 damage per round, then it would take just over 3 rounds to defeat the monster. Then you figure in that there are 3 of these monsters in the combat scenario making it closer to 10 rounds to take them out.

We then take the party of four, a total of 63 hp and see that the monsters deal 84 damage per round (28 per monster). This means that it's possible that the monsters could take out the party in one turn, assuming multi-attack, or 2 rounds assuming one attack for each monster.

These numbers would indicate that it's a deadly/impossible encounter. However, how do you take into account things such as Healing, Barbarian Rage, riders from spells that could hinder the opponent, or conditions like Prone? These effects can seriously change the tide of battle and make things exceptionally easier. Some of the effects could be easily calculated, such as Rage, but others are a bit trickier I feel.

While it's not my intent to generate combats that are built to stymie the group, I think it might be helpful to have a way to take that into account for a combat generation tool.

[MarkVIIIMarc]

I'm working on some tools that I can use to steamline my job as a DM. I have a spreadsheet for generating random adventures using all the tables from the DMG. I have another one for generating random NPCs and Villains, again using the tables from the DMG. I'm working on a spreadsheet that will allow you to custom build a creature with all the calculations done for you and customize almost every aspect of it. I'm working on a random encounter spreadsheet to handle social, combat, and environment/location encounters for those long treks across the map or whenever. These projects are my way of keeping busy when I'm not in the mood to do real adulting. However, I've found myself asking a question that I'd like some input on and it deals with CR calculation for encounter difficulty and high level and/or large groups:

What information is missing from the CR calculations/Combat Difficulty to help mitigate the apparent dramatic drop in challenge at higher levels or with larger groups? Many of us have found that CR is a good baseline for combat generation but it starts to fall short after a while. We've learned to add strategy, environment and other factors into a combat to make it more challenging to our players. We've got a few buttons and levers we can play with to make a creature more durable or hit harder. The goal here is to give a tool for both the novice and experienced DM that can help calculate a combat encounter much closer to the capabilities of the party they're working with. So, again, what do you feel is missing from a CR calculator that would make the end result more accurate?

Higher level PC's are generally run by more experienced players. Heck, somewhat for and against your idea, in a game I play in, we've been level 7 for 30ish sessions because the DM doesn't like higher level encounters. We're getting pretty decent at being level 7 whatevers we are.

So, the DM has to get more experienced also and use the terrain and advanced tactics or else the CR gets off that way.

Also somewhat for what you are saying, the save or suck spells that come along make combat real swingy.

[Unoriginal]

So, with what you're suggesting, you take "Monster A" vs a party of four and figure that if Monster A has 86 HP and the party can dish out an average of 26 damage per round, then it would take just over 3 rounds to defeat the monster. Then you figure in that there are 3 of these monsters in the combat scenario making it closer to 10 rounds to take them out.

We then take the party of four, a total of 63 hp and see that the monsters deal 84 damage per round (28 per monster). This means that it's possible that the monsters could take out the party in one turn, assuming multi-attack, or 2 rounds assuming one attack for each monster.

These numbers would indicate that it's a deadly/impossible encounter. However, how do you take into account things such as Healing, Barbarian Rage, riders from spells that could hinder the opponent, or conditions like Prone? These effects can seriously change the tide of battle and make things exceptionally easier. Some of the effects could be easily calculated, such as Rage, but others are a bit trickier I feel.

While it's not my intent to generate combats that are built to stymie the group, I think it might be helpful to have a way to take that into account for a combat generation tool.

No, that is not what I am suggesting.

What I am suggestion is:

-Take the NPC side, define their victory conditions
-Take the PC side, define their victory conditions
-Calculate how long on average it would take for each group to accomplish those victory conditions, when opposed by the other group.

And then you'll have an accurate Encounter Difficulty rating.

Ex: 8 goblins want to capture the PC group 1 Cleric, 1 Barbarian, 2 Fighters (all of them lvl 2) and 1 Wizard/Rogue (lvl 1/1). The PC group want to avoid that. They are in a forest the PCs don't know about.

Now calculate how fast the groups could accomplish their objectives, using optimal tactics.

[DMThac0]

Higher level PC's are generally run by more experienced players. Heck, somewhat for and against your idea, in a game I play in, we've been level 7 for 30ish sessions because the DM doesn't like higher level encounters. We're getting pretty decent at being level 7 whatevers we are.

So, the DM has to get more experienced also and use the terrain and advanced tactics or else the CR gets off that way.

Also somewhat for what you are saying, the save or suck spells that come along make combat real swingy.

Save or suck spells really do have a habit of making the best laid plans go awry...Dispel Magic has been the most recent spell to foil a plot I had set up for my players...so much work done in by a brilliant use of a spell.

From what I gather, you're saying that much of what makes the difficulty of an encounter hinges on how well the players/DM understand the tools they're working with. With that, do you think there's a way that a tool could be implemented to make your DM's job easier handling the higher tier encounters or do you believe it sits firmly on the necessity of the players/DM learning more about the game, their tools, and it's mechanics?


No, that is not what I am suggesting.

What I am suggestion is:

-Take the NPC side, define their victory conditions
-Take the PC side, define their victory conditions
-Calculate how long on average it would take for each group to accomplish those victory conditions, when opposed by the other group.

And then you'll have an accurate Encounter Difficulty rating.

Ex: 8 goblins want to capture the PC group 1 Cleric, 1 Barbarian, 2 Fighters (all of them lvl 2) and 1 Wizard/Rogue (lvl 1/1). The PC group want to avoid that. They are in a forest the PCs don't know about.

Now calculate how fast the groups could accomplish their objectives, using optimal tactics.

Alright, do you think there is a way to make this an applicable algorithm or do you feel that this is an arbitrary system that rests on each table individually?

[Unoriginal]

Alright, do you think there is a way to make this an applicable algorithm or do you feel that this is an arbitrary system that rests on each table individually?

There is no way to create an algorithm that takes all the factors and variables plus things like DM's calls into account.

That's why the writers went with the CR system rather than trying to actually calculate the encounters' difficulties.