How do you measure challenge rating?

[imp_fireball]

Is there an effective means?

For this, I want to include CRs below 1; in the srd, there are CRs that count as 1/2 or 1/4 even.

So here's some samples to go by:

- A level 1 orc warrior (1HD), with average stats and hp, a falchion and a chainshirt.

- Another level 1 orc warrior with 22 STR, 18 CON, full hp, a greatsword and spiked fullplate.

- The same orc but with magical items and even twinkier stats, etc. (the list goes on)

Both technically have ECL 1, but wouldn't the challenge rating vary?

----------
My intention is to find a way to perfectly measure up combos to a 3.5 game. Magic items can change the CR of a PC/NPC, however all PCs would begin at the same class level + LA.

I want to be able to include technology as a paradigm of 3.5 to make setting more convenient. As such, some technological items (powered armor, ie.) might include an LA, or perhaps XP equivalent level adjustment buy down in order to learn to use.

The simplest example of technology in 3.5 core is the composite bow, which a character can pay additional money for to strengthen the drawstring, such that it requires more STR to use effectively but deals more damage (of course, it is treated as STR 10 initially, but at that stage any STR score can use it oddly enough).

[afroakuma]

It's essentially impossible to accurately assess CR or assign values to defined abilities.

For the rough CRs that I employ, I use Vorpal Tribble's method:


1. Divide its average HP by 4.5 to 6, 4.5 for 5 HD or lower, 5 for 6-10 HD, 5.5 for 11-15 HD, 6 for 16-20 HD.
2. Add 1 for each five points above 10 its AC is, minusing 1 for every 5 below.
3. Add 1 for each special attack (+2 to +5 or more if its got a decent number of spells in its spell-like abilities).
4. Add 1 for each quality unless you deem it worthy of more. Add 1 for each resistance and 10 points of DR it has, and 2 for each immunity.
5. Add 1 for every two bonus feats it has.
6. Divide by 3.

[imp_fireball]

That might be good enough, although I'll have to run some calculations.

EDIT: The semi-optomized orc warrior in spikey metal armor has 2/3 CR. Good enough?

Some more

Zergling - CR 6. It's my iteration and for now I'll admit that it has a chock load of qualities that could use stripping down to create the base creature (some of the stats provided are also peaked when they should be averaged).

Baby - Couldn't get accurate results with the baby having 0hp, -5 DEX and a dozen other special qualities that include DEX not applying to AC (even though humanoid (human) babies have increased DEX to some circumstances in their stage of life) and not being considered dying or (stable) despite being at 0hp, unless it falls into the negatives. One of the calculations made it look like 1/10 CR, but I'll just throw out a statement of it being 1/20 CR for now. It could be even lower though considering babies don't even fight back unless you want to give it an int of 20, which gives it a language, and make it an evil genius that bites for non-lethal (assuming its teeth have grown in); although you might have to include some other traits as well.

Say for Stewie, he'd have all the traits of a martial artist, more than 0 hp, plenty of Knowledge: Science and Technology ranks, but with the major flaw of being forced to submit to vile red haired women or at least those of parental relation to him.

-----------------------
The only trouble with this system is that 'special quality' is a matter of opinion; while it's somewhat obvious what a special quality is, it's difficult to compare to other special qualities. There's also NPC/PC role involved.

Powered Armor that multiplies a PC's strength by a factor of five would be a massive 'special quality' for an item compared to regeneration 5, although some would argue that regeneration is better because it allows the latter to recover even after being smashed into a bloody paste by the former.

Finally, special qualities granted by templates should not count sometimes, unless they're 'big' qualities like regeneration. Otherwise, you might find the average stat troll that was given a CR 5 in the SRD a 6.
------------

3. Add 1 for each special attack (+2 to +5 or more if its got a decent number of spells in its spell-like abilities).

What does the second bold part mean?