D20 Challenge Ratings

[Gary N. Mengle]

After much tooth-gnashing, I'm thinking of running a d20 game (for the first time,) so I'm giving the rules a thoughough going-over before I make a call one way or the other.

My question is, how well do Challenge Ratings work as a tool for balancing encounters? They look about right to me, but I don't have enough time in d20 to be confident in making that assumption.

Also, how are GMs handling the use of Challenge Ratings for parties of less or more than 4 characters? The DMG basically waves its hand at this.

My immediate thought is, instead of simply averaging the party's levels (as the DMG suggests, regardless of party size,) adding all the levels up and dividing by 4 to get an adjusted Encounter Level.

Seems like it would work to me. Anyone else have any thoughts on this?

[mearls]

Adding the party's levels and dividing by 4 messes up the CR system. One of the factors that goes into balancing a CR is the spells and magic items available to characters of a given level. Thus, a CR 9 monster has that rating under the assumption that parties at its CR or above in level have access to 5th level wizard and cleric spells. Thus, 6 6th-level characters, the equivalent of a 9th level party if you divide their levels by four, could be dogmeat, since they only have 3rd level spells, max.

Larger parties are penalized by the division of XP. A party of 6 faces more encounters to gain levels than a party of 4, all other things being equal.

- Mearls

[Gary N. Mengle]

Hmmm, I see what you mean. Which points up another potential flaw in the CR system... that if the GM isn't giving out close to the "standard" number of magic items, the party may be under- or over-powered by an encounter of what the system says is the appropriate Encounter Level, based strictly on party levels.

It does seem to the, though, that CRs ought to be a means to balance the encounter itself, rather than just the experience gained thereby. Still, it's a more useful tool than anything 2nd ed. had.

[Staffan]

Originally posted by Gary N. Mengle
My immediate thought is, instead of simply averaging the party's levels (as the DMG suggests, regardless of party size,) adding all the levels up and dividing by 4 to get an adjusted Encounter Level.

I would suggest reverse-engineering the rules for encounters with more than one monster instead. 4 "monsters" (the standard party) are worth +4 to EL. 2 monsters are only worth +2, so a 2-PC party should probably have a "standard" encounter with an EL of 2 below their own level. Likewise, a party of 5 or 6 characters should have an EL of 1 above their level, and a party of 7-9 characters should have an EL of 2 more.

[Jan-Willem van den Broek]

Originally posted by Gary N. Mengle

My question is, how well do Challenge Ratings work as a tool for balancing encounters? They look about right to me, but I don't have enough time in d20 to be confident in making that assumption.


I've had few problems with them, as long as the CR given is realistic given the creatures combat capabilities. However, this is quite often not the case. The creatures in the MM are mostly fine, but many third-party creatures have weird CRs, as do some in Monsters of Faerun (a certain dragon-like creature springs to mind. It has CR 5, but would be a pretty tough opponent for a level 8 party).
Also, something you should be aware of is that the CRs assume you have a 'balanced' party (fighter+rogue+cleric+mage). Several monsters will be significantly tougher if this is not the case. For instance: undead will be much tougher if the party has a lot of rogues ('sneak attack' is ineffective against undead) or a shortage of clerics/paladins (the only classes with 'turn undead').

Hope this helps.

[Jan-Willem van den Broek]

Originally posted by Gary N. Mengle
Also, how are GMs handling the use of Challenge Ratings for parties of less or more than 4 characters? The DMG basically waves its hand at this.

My immediate thought is, instead of simply averaging the party's levels (as the DMG suggests, regardless of party size,) adding all the levels up and dividing by 4 to get an adjusted Encounter Level.

Seems like it would work to me. Anyone else have any thoughts on this?

Hmm, forgot about this one in my previous post.

I personally just use the DMG's system. I average the party's level, and cross-reference it with the Encounter Level to get the amount of xp the party (!) receives. Since there are more characters in the party, each will get a smaller slice of the party's xp and it all balances out.
I've had no problems so far... (as long as the CR was somewhat realistic).

[Sangrolu]

Originally posted by Jan-Willem van den Broek
I personally just use the DMG's system. I average the party's level, and cross-reference it with the Encounter Level to get the amount of xp the party (!) receives. Since there are more characters in the party, each will get a smaller slice of the party's xp and it all balances out.
I've had no problems so far... (as long as the CR was somewhat realistic).

Ah, but you have two things going on with the CR system here. You are assigning XP, and you are balancing encounters. The effect you talk about is fine for assigning XP. It's not so good for balancing encounters.

For balancing encountters, an "even on" (i.e., it could go either way, a dangerous encounter) is based on 4 creatures with CR = the party average. So what you can do is use the same scale the monsters use to tweak the effective encounter level (EL). Subtract four from the modifier in the DMG and invert it. The math works out as follows:

Party
Members EL Tweak
1 +4
2 +2
3 +1
4 +0

As for how well it works... I find that it works pretty well. Sometimes surprisingly well. Just last friday I started a new 4th level party. I faced them with 3 half dragon worgs. (Worg = 2, half-dragon +2, 3 = +3, total 7). I figured they could handle it, but in truth it became obvious to me fairly early on that they were going to take casualties. (So I spontaneously morphed them into half-dragon normal worlves.)

It isn't perfect, however, it that it is not sensitive to situations, and the statistical "spread" gets higher as you go up levels. The abilities and tactics of the party can make a massive difference. Take the collossal scorpion, for example. A typical high level party has the magic and ranged attacks to make short work of this creature. But in a low-magic campaign and if the party is trapped in close to the thing, it can be a living terror.

So the thing to do whenever you face the party with a creature is ask yourself "is there anything about the party or the situation that will make the encounter tougher or weaker than normal?", and apply the EL modifiers in the DMG for the situation.

For example, right now I am running a party with two members that are totally immune to lightining and cold. Encounters with creatures that rely on these attack forms will obviously be a little easier for the party.

The thing to keep in mind is that CR and EL are a guide, and can't substitute for your knowledge of the party and the situation.

[Jan-Willem van den Broek]

Rats! You're right Sangrolu, it appears I should read more carefully.

I heartily agree with your conclusion by the way: party knowledge is essential in balancing encounters. A few things I always pay extra attention to are mind affecting attacks (as we usually have a barbarian or rogue with a low will save and who could easily kill one or two party members), ability/energy drain attacks (as we usually have a shortage of clerics to remedy the situation) and monster/npc intelligence (my players are occasionally extremely stupid, so this makes for a HUGE advantage).

EDIT: minor typos.

[Cam Banks]

One of the more common problems I encountered with the CR system (and the associated nature of Encounter Levels) is that the game is designed around groups of 4 player characters, which isn't as common for me or my group.

I realized when converting the DL series of Dragonlance modules that they were designed for a party of 8, and that sending a party of 4 through them would be much more dangerous. Rather than scale it down, I simply worked out that every doubling of your PCs means they can handle +2 to the EL. Thus, DL1's party of 8 characters with an average level of 5 could handle an EL 7 as a "challenge", where only 4 would be able to handle an EL 5.

6 player characters can handle +1 more EL, so if you have 6 PCs (like my Elizabethulhu game has, more often than not) it only nudges the challenges a little back towards the easy mark.

One last thing to consider is the monster or encounter itself, as has already been pointed out. I have found that many lesser CR creatures can be more of a challenge than one higher CR creature, especially if the bigger one hasn't got multiple attacks. Sending hordes of weak monsters with one or two annoying features (my favorite for a while were fiendish baboons, with the smite good ability) can be quite difficult to deal with.

Cheers,
Cam

[Arauthator]

Ok, this is a very OLD issue, but since we are on the brink of fourth edition, I would like to revisit this.....because I love the CR system with the twist of those rules I've been using ever since third edition. Actually all the way back to eighties.

How does putting up a party of four level seven characters against a CR 20 sound to you? Baphomet Prince of Beasts is the example I will use here because my party took him down at seventh level. Sort of.

First off, my rules are expanded upon by a few suggestions I've picked up on these boards and over at WoTC. Some players have suggested in the past to add the levels of the PC's instead of using an average. I for one loved the idea, but when the matching monster hit a crit.......disaster followed. But I found a way around it. Creativity and the Gary way.....Keep It Simple Stupid.

Second, I am going to attempt to get you in a right frame of mind on this CR system, which I would personally hate to see WoTC get rid of. Skip, Monte, and Jonathan had it right, almost. I don't think it's in bad enough shape to be totally dropped though. I just think using averages of PC parties is ok until the PC's start picking up magic items. Without creativity, it's a hard match up.

Third, you need to be a player for a long time like myself to understand where my idea originated from, because it has a Gary Gygax touch to it. Yet another Genius in the DnD world like Skip and the boys, and let's not forget he is the Father of this game. I hate it that he has been forgotten in today's d20 system and so many writers have gotten away from his rules system when it wasn't that bad from the get go. It worked and we had just as much fun in 1980 as we do today.

Ok, here it goes. You have to be privy on the movie Spiderman to follow along.

Want to save babies do ya?
Remember when Spiderman was in the burning building in the first movie, saving babies? He is taken by surprise by the Green Goblin and knocked on his butt. By a very nasty blow I might add. Well, he doesn't die because Spiderman is loaded with AC. No, he gets back up like hero's do. Fire all around the place, nasty tap on the chin, bouncing off burning boards, and still has the Hit Points to get up and fight. Green Goblin doesn't like it that Spiderman won't join forces so he throws a handful of ball type blade grenades at Spiderman. What does the super hero do? Dodges everyone of them like something out of the Matrix movie and commences to get his ego bruised. He just got his super powers only but a few days before this battle as well and that represents a PC who is still wet behind the ears. If you count the attacks Green Goblin dishes out, he attacked, counting the ball blades, 12 times before Spiderman got in 2. So you have the Green Goblin, Fire resistant, Rocket shooting machine gun power sled with ball blade grenades and strength of human spider as well. What does Spiderman have in this battle? A web.

So, let's take this fast action battle that is one of my favorites out of any movie, and analyze these feats the DnD way. We have established a villain with a CR I would call 20, against a super hero of Level 7. He has no magic, only webs and agility with some super strong strength. All of those features of Spiderman make up AC in the DnD world. Say hello to Baphomet meeting a PC Party level of 7. If the Green Goblin were to hit Spiderman with one of those Rockets, or the Machine Gun, Spiderman would be no more. That story would have sucked. No, instead we have 2 people that are to meet up at Grandma's house in the next few minutes and Spiderman ran away because super hero's should be punctual. Always my favorite thing to do before a family gathering, by the way, take out a local super hero and eat some Turkey. While the story may be a bit cheesy, the action in that scene was totally cool.

Can Spiderman come out to play?
Next, we move to the Green Goblin at his mischievous tricks again while singing nursery rhymes. This time, Green Goblin ends up with giving the Super Hero a choice. EXCELLENT tactic for the DnD game while placing a Demon Lord from the Abyss in front of the Characters. Save the people, or save your first love? Hmm, what to do? I got it! Let's save both! This battle, Green Goblin dishes out 15 attacks with the bomb included and Greeny is really pissed off. Finally, Spiderman gives a blow back by a kick and pulls a wall down on Green Goblin. Couple more punches by Spiderman and ol' Greeny pulls out yet another trick. Now get ready for the 1 roll on the 20 sided. Green Goblin pulls his rocket ride up behind Spiderman, who would be considered flat-footed, but Spiderman jumps out of the way in a flip flop from hell. End of Green Goblin as the sled rides right by Spiderman and pins him against the wall and the CR 20 creature, Green Goblin, is now dead. Do you award XP for this kill? Certainly not, but the writer sure played him well, that's got to be worth some XP. I'm thinking appropriate XP for a level seven.

Guys, that's what a battle in DnD is ALL about right there. That is what Gary meant by creating this game and that is how it should stay. I see way too many conversations over rules or about CR and not enough emphasis on the creativity of how you use the monsters and villains in the game. Players....who are you? You're Spiderman. Standing in front of a monster throwing dice down on the table is never going to make you satisfied versus throwing in some action like that example I just laid down for you. Spiderman has nothing but AC in his battles, sure he took half damage on the crit the bomb threw down on his face, but how many magic items come to mind to get this effect off the top of your head? I could think of about 20 myself. This is how you get a nice monster to the PC's without making them wait until Epic level to enjoy the fruit. You don't need to totally eradicate the idea. I was just getting use to it WoTC. No, what you need is some really good games on video tape for everyone to watch off your website. A DnD youtube section covering specific sets of rules and showing off your great game.

In closing, those are my rules. I have used those tactics since the eighties and still use today. But hey, I am a huge fan of Gary Gygax and that's just me, an old fart, well not as old as Gary, but one approaching his fourties. Never-the-less, I know the comics and LOTR very well since I grew up on those stories and if you take ideas like that from authors who have contributed so much to the fantasy world, you are going to throw down one awesome day at the table every time you take your PC's into battle. So WoTC, I understand your want to make things fresh again, but I'll stick with the 3.5 rules this time. After watching this game evolve into what it is today, you can have the fourth edition, dice rolling, miniature mongering, no plot heavy, rules arguing, I'm eating all your Funyuns for that by the way......style of gaming. You really hit me big time by catering to the cry babies with no imagination in this fabulous game. I would have to say you pulled exactly the same trick Green Goblin pulled on Spiderman in the burning building by creating another edition.

Game On!
Or Funyun!

[Pete Whalley]

Holy thread necromancy bat...uhh, spiderman?

On topic though, I'm not a fan of the CR system. A major factor in figuring an appropriate CR is the christmas tree effect of magic items, and their importance to 3.x.

Since I'm a stingy bastard DM who likes to keep my adventurers on the lower side of the loot equation, I ended up dropping CR's as a yardstick ages ago. Nowadays I just keep a record of the player's character sheets and eyeball them as I pick monsters.

Either that or run through a quick few rounds of sample combat to simulate a beasties toughness and weak points- course this only works when you know your player's style well.
Now, let's sit back and countdown to the thread move. :)

[filigree]

Challenging Challenge Ratings, by Craig Cochrane, is a good place to start.

CR is a wonderful idea, and with the application of some logic, and not a little perseverance, it can be made to work quite well.

[Agent Oracle]

Here: Use This Link:

Encounter Calculator (http://www.geocities.com/edymnionii/EPLvsEL.html)

it's a quick and easy means of calculating appropriate challenge ratings for parties of any size / ECL mixture

Put your Heroes in the left columns, put their adversaries in the right columns.

[Damerax]

Having GM'd with CR system for a good while I find it's usually ok for most monsters but tends to not work out so well if as has been pointed out you don't have 4 party members. The environment has a huge impact too, for instance: a party of 7th level characters are not gonna have a problem against say 2 or 3 CR 4 griffins but how about the party is scaling the side of a mountain and they get attacked by those griffins?

Some monsters of course make no sense for their CR like admanitine clock work horrors being CR 9 and having implosion at will (a 9th level spell). The big problem I have is there are no real guidelines to assigning CR's to monsters of your own creation, just have to compare monsters with similar abilities and guess really.

Here's a decent encounter I ran through using low CR monsters: On the run from hostile forces the players flee into the swamp, after camping they awaken to mist as thick as pea soup, an uncomfortable silence descends when in the distance low moans echo through the mists. With unstable ground and sinkholes everywhere and no visibility the players try to navigate out but now the moans are closer and coming from every direction, the stench of rotting flesh permeates the air. Of course the players are attacked by...zombies!

For six 5th level characters easy as pie as they lay into them easily destroying them, unfortunately the bodies bloated from the swamp waters explode as they die spraying chunks of diseased meat all around (another variant was to release a cloud of sleep gas). Ranged attacks are useless and up close they take damage, while trying to avoid grasping hands pulling them into sink holes...

For a bunch of CR 3 monsters the party almost got wiped out, point being location, location, location :D

[Anwar]

Either that or run through a quick few rounds of sample combat to simulate a beasties toughness and weak points- course this only works when you know your player's style well.

The problem I have with D&D monsters is that they don't function the same way regarding the threat they are representing.
Big brutes (who only have strength) are a relatively easy foe to calculate. After all, the best they can do is score a crit on a single player. Ablative HP mechanics ensure that the threat remains easy to calculate.
Then there are monsters with all kinds of weird abilities - and some of these abilities can mean an instant TPK with a bit of bad luck. I once had an entire 5th level party killed by 2 harpies (a CR 4 monster) by virtue of their captivating song ability.

- Anwar