Dungeons and Dragons Challenge Ratings
Nov. 19th, 2007 01:55 pm![[personal profile]](https://www.dreamwidth.org/img/silk/identity/user.png){kind=small}
jackIn DnD, monsters are assigned a challenge rating, and approximate measure of how hard they are for an average party of adventurers to defeat.
The challenge ratings are obviously ordered[1], but the question remains, what scale? There are two obvious candidates.
(a) Linear. A CR10 monster is as difficult to defeat as two CR5 monsters[2]. This has the obvious advantage of being easy to add.
(b) Logarithmic. A CR10 monster is as difficult to defeat as two CR9 monsters. (In actual fact, there's an arbitrary scaling factor, it supposedly equals two CR8 monsters.) This has the advantage that it matches character progression by level, and notionally monster progression by hit dice (related to character level). This means a CR10 monster is appropriate for Level 10 adventurer characters, and might well have 10 hit dice, or at least hit dice proportional to 10.
Go on, guess which method they used. I'll give you a clue, it seems the worst possible.
That's right, they used both. (a) for CR<=1 and (b) for CR>=1. (In actual fact, this makes some sense -- you often would use CR<1 monsters only with each other. But it still seems very arbitrary. Not that I care, but it amused me :))
Footnotes
[1] Is it obvious? Well, in actual fact, you might easily have rock-paper-scissors monsters, but because they're defined in terms of the average party, the challenge ratings *are* transitive. Also anti-symmetric.
Is it a well-order? Well, the monsters listed anywhere, there are only finitely many of them, so yes. And if you consider typical attributes of monsters, eg. health, strength, damage output, these are defined by positive integers, and lower is weaker, so of any such set, there'll always be a weakest.
However, it is conceivable to have a set of unboundedly weak monsters. Let there be a monster, a proto-nth-orc[3]. This has, on encountering adventurers, a 1/n chance of morphing into an orc, and an (n-1)/n chance of disintegrating entirely. This obviously has a challenge rating of approximately 1/n that of an orc -- so the set of all such meta-nth-orcs is ordered, but has no least member.
[2] The "two together" is an approximation, it's incredibly situational, but it's the standard to start working from.
[3] I so want to throw this at some players now :)
The challenge ratings are obviously ordered[1], but the question remains, what scale? There are two obvious candidates.
(a) Linear. A CR10 monster is as difficult to defeat as two CR5 monsters[2]. This has the obvious advantage of being easy to add.
(b) Logarithmic. A CR10 monster is as difficult to defeat as two CR9 monsters. (In actual fact, there's an arbitrary scaling factor, it supposedly equals two CR8 monsters.) This has the advantage that it matches character progression by level, and notionally monster progression by hit dice (related to character level). This means a CR10 monster is appropriate for Level 10 adventurer characters, and might well have 10 hit dice, or at least hit dice proportional to 10.
Go on, guess which method they used. I'll give you a clue, it seems the worst possible.
That's right, they used both. (a) for CR<=1 and (b) for CR>=1. (In actual fact, this makes some sense -- you often would use CR<1 monsters only with each other. But it still seems very arbitrary. Not that I care, but it amused me :))
Footnotes
[1] Is it obvious? Well, in actual fact, you might easily have rock-paper-scissors monsters, but because they're defined in terms of the average party, the challenge ratings *are* transitive. Also anti-symmetric.
Is it a well-order? Well, the monsters listed anywhere, there are only finitely many of them, so yes. And if you consider typical attributes of monsters, eg. health, strength, damage output, these are defined by positive integers, and lower is weaker, so of any such set, there'll always be a weakest.
However, it is conceivable to have a set of unboundedly weak monsters. Let there be a monster, a proto-nth-orc[3]. This has, on encountering adventurers, a 1/n chance of morphing into an orc, and an (n-1)/n chance of disintegrating entirely. This obviously has a challenge rating of approximately 1/n that of an orc -- so the set of all such meta-nth-orcs is ordered, but has no least member.
[2] The "two together" is an approximation, it's incredibly situational, but it's the standard to start working from.
[3] I so want to throw this at some players now :)
no subject
Date: 2007-11-19 06:19 pm (UTC)But now I wonder if chance of dying would make a good measure in addition to the traditional system -- it's objective, and the second axis would formalise another important aspect of evaluating an enocunter.
(c) is what it's *supposed* to measure. Though (b) is probably closer to what it *does* measure, as all the non-linearities in combining monsters aren't taken account of in the formula.
And in DnD you're either on your feet with full strength, or dying, your effectiveness doesn't really drop. (For spellcasters, that's "have spells left" or "have no spells left"), so (b) doesn't make that much difference.
Actually, I guess there's approximately two timescales that matter. Overnight, you regain spells, and maybe go back to base and renew equipment. Over a few minutes, you can cast healing spells, drink potions, pull people out of pit traps, etc.
Fighting monsters consecutively would be close to "fighting monsters concurrently, but ignoring synergies", which is what they're supposed to measure.
I'm not sure if the term "resources" better tracks hit points or healing potions, or even if it's that well defined (it's certainly not that well thought out :)) That's the end of my musings for this post -- note, this is *mostly* theoretical on my part, I've played some, but not a lot.