in Dungeons and Dragons 3.5 Monster Manual, they do by the 10/11 Rule for Dice, so to find out the ability score adjustment I would just subtract 10 from even scores and 11 from odd scores. So, take Nymph for example:
Str 10 - 10 = 0
Dex 17 - 11 = +6
Con 12 - 10 = +2
Int 16 - 10 = +6
Wis 17 - 11 = +6
Cha 19 - 11 = +8
D&D Nymph Ability Adjustments: +6 Dex,
+2 Con, +6 Int, +6 Wis, +8 Cha
But looking in the Pathfinder Bestiary has me a bit confused.
Str 10 - 10 = 0
Dex 21 - 11 = +10
Con 18 - 10 = +8
Int 16 - 10 = +6
Wis 17 - 11 = +6
Cha 25 - 11 = +14
Apparent Pathfinder Nymph Ability Adjustments:
+10 Dex, +8 Con, +6 Int, +6 Wis, +14 Cha
Does Pathfinder use the same 10/11 rule, and if so, does that mean Nymph as a character got that much stronger without a challenge rating increase? Or is there some new system for figuring out an Ability Score adjustment of a monster?
And on a side note, how would you adjust the challenge rating of a monster that has as many levels of spells as it's challenge rating if you removed all those spells and gave it a different class in a story? For example, what would a Nymph's Challenge rating be with no spells but everything else?
Thanks.