(PF) Adjusting HP's affect on CR

[Sylthia]

How much does changing an NPC's HP affect the CR? Say Bob the Dwarf has a CR of 6 with 70 HP, 20 AC, +9 Fort, +4 ref, +4 will and wields a +2 falchion +13/+8 that deals 2d4+10 damage. If I keep all other thing equal, but drop his HP to 35, how much would that drop his CR if at all?

I usually just wing it when calculating CR and usually make challenging encounters while avoiding TPKs, but I'm wondering if there's a chart for this.

[herrhauptmann]

Probably drop CR by 1, if that.
He's still just as deadly on the offense, even if his HP are equivalent to CR 3s and 4s.

There might be some guidelines in the DMG, but I'm not sure what page.
Even then, they're guidelines. Take a bag of HP and double its HP, particularly when it's already got good defenses and/or regen of some sort, and it'll probably be a bit more than a CR +1.

[Mcdt2]

I don't think there's any chart for this (at least, not in any 1st party stuff I've seen.) I do however, have a book somewhere that lists out the average stats of monsters in the MM1. Consulting it, I see that CR 6 monsters have an average of 8 HD, 18 AC, +11 to hit, +9 to good saves, and +4 to bad saves, before magic items. Seems more or less spot on for our dwarf.

Now, I'm assuming Bob is a straight classed fighter, level 6, based on the stats and the dwarven favored class. Now, he already only has 6 HD, which is the average for CR 4 monsters. Decent HD size and good Con helps make up for that, but still. Extrapolating here, I'm assuming he has a Con of at least 20, because average d10 rolls plus con mod for 6 levels gives us 66 HP, pretty close to 70. Hlaving his HD (and thus his hp) would put him on the level of a CR 2 monster (avg of 3 HD). But of course, he still has the attack of a CR 6 creature. I would call him a CR 4 monster.

This being said, all the attack boni in the world won't save him when he's sneak attacked into oblivion the first turn. In fact, I typically double or even triple the HP of any monster I throw at my party, without any CR adjustment. Personally, I distrust the CR system. In fact, I would throw it out entirely, most of the time. Failing that, I redistribute the games concepts of "challenge". Specifically, I call a CR=ECL fight a pushover fight, not a standard one. Standard for my party is ECL+2 or even +3. Moderately Challenging fights are about ECL+4, and ECL+6 makes a good boss fight. And I wouldn't call my party optimized in the least. I've had Vow of Poverty/Peace Monks in my party before. Certainly was an interesting campaign, at least.

[Ravenica]

the details for adding or removing hit dice is in the back of the bestiary and can be found on the PRD and includes a table for just what you want

clicky mcclickerson (http://paizo.com/pathfinderRPG/prd/monsters/monsterAdvancement.html)

[Sylthia]

Thanks for the pointers. I agree, going by the book CR seems a bit easy. A group of 2 same level fighters doesn't seem much of a challenge for a well composed party of 4.

One thing I liked about 4th edition was the idea of minions. Sometimes I want to have a small army of Npcs to fight, but if they all have full HP, the fight might be harder than intended or just drag on too long.

Oh, Bob had 70 HP instead of 66 because I gave him max HP at first level. His stats were Str 18 Dex 14 Con 18 Int 8 Wis 14 Cha 6. A bit powerful for an NPC, but not overwhelming. He got an extra +1 HP per level from having class levels. Nice analysis, though. I guess I'll just follow your advise and keep doing what I've been doing and ignoring CR.

Bob's one of my generic NPCs I like to have on hand in case I need to make an encounter on the fly. I usually have a few index cards of them.

[AttilaTheGeek]

Thanks for the pointers. I agree, going by the book CR seems a bit easy. A group of 2 same level fighters doesn't seem much of a challenge for a well composed party of 4.

One thing I liked about 4th edition was the idea of minions. Sometimes I want to have a small army of Npcs to fight, but if they all have full HP, the fight might be harder than intended or just drag on too long.

Oh, Bob had 70 HP instead of 66 because I gave him max HP at first level. His stats were Str 18 Dex 14 Con 18 Int 8 Wis 14 Cha 6. A bit powerful for an NPC, but not overwhelming. He got an extra +1 HP per level from having class levels. Nice analysis, though. I guess I'll just follow your advise and keep doing what I've been doing and ignoring CR.

Bob's one of my generic NPCs I like to have on hand in case I need to make an encounter on the fly. I usually have a few index cards of them.

I played a Pathfinder game where the DM tried introducing minions to test the waters. Please, don't do this. Ever. Are your melee feeling outclassed by the casters? Do your rogues do awful damage? Maybe your strikers are feeling a little too squishy with no way around it? Minions make all of these problems worse. There's nothing like "I sneak attack for... *roll roll roll* HA! 79 damage!" "Would now be a bad time to tell you that monster had three hit points?"

[Sylthia]

I played a Pathfinder game where the DM tried introducing minions to test the waters. Please, don't do this. Ever. Are your melee feeling outclassed by the casters? Do your rogues do awful damage? Maybe your strikers are feeling a little too squishy with no way around it? Minions make all of these problems worse. There's nothing like "I sneak attack for... *roll roll roll* HA! 79 damage!" "Would now be a bad time to tell you that monster had three hit points?"

1 HP might be a little extreme, but having a quarter of regular HP might be okay for some scenarios.

[awa]

there nothing wrong with the design concept of minion type characters ive used them for years with no complaints (although im defining minions as targets that can be killed by a single attack from a primary weapon rarely actually 1 hp) your high damge attacks are useful for elite foes and bosses.

there is no blanket answer for how changing hp affects cr