Sunday, March 6, 2011

Straining at motes, part 3

Kobold said...
Dr Allthumbs, with a negative DM for his DEX, has an effective Skill of, what?, Medic 1?
Actually, on the table I'm testing, he'd only have a -1.  But I get your point.
But, and this is an important but, only in situations where he has to use his DEX.

As a consulting physician, he can identify Interstellar Blot by just looking the patient in the eye and sampling his urine. As a surgeon, he is a skilled butcher, and probably doesn't do much cosmetic work.

Dr Giftedpratt, on the otherhand, both knows his stuff, and can perform delicate keyhole surgery on eyeballs, and other bits you don't want a cleaver-monkey fiddling with.
March 5, 2011 1:09 AM
Good points.  So, it seems that hard cutoffs where the stat allows you to do something help the issue- if I recall, CT had a DEX requirement along with Medic 3 to be a surgeon, and having stat minimums for use of weapons without a minus dm.

Second, the effect of stats are more situational than skills.  Which makes sense, especially with fairly broad skill categories.  It's not hard to imagine that most of the very high level skills could have different situations where different stats are important.  In which case, does capping the plus or minus mods at +/-1 for most situations seem enough ? With -2 being a big penalty ?

I am coming to think that part of the problem is that the perceived value of a modifier is based on its observed effect on a d20  system roll.  Thus, in a d20 system a +/- 1 represents a 5% difference and seems particularly trivial. However, in a 2d6 system, a -1 on an otherwise straight roll for success (8+) reduces the likelihood of success by 14%,  from ~42% (8+) to ~28% (9+);  almost three times the effect of a d20 +1.

So we see that not only shouldn't Dr Allthumbs be considered a surgeon (using a hard requirement for DEX), he would have a non trivial penalty to his likelihood of success vs Dr Giftedpratt.  Assume Medic 3 for both, with one having a +2 (12 DEX) and the other having a -2 (2 DEX), the chances of success are  ~58% (thumbs) and ~97% (gifted).
With a +/-1 for DEX  we have 72% vs 92% success, still a 20% difference. And remember we are talking about surgery that 20% represents life and death in many cases.

Given those numbers it seems to me that input from stats of 1 or 2 is quite enough -especially if there are some tasks with a hard requirement.

One thing: thanks to input, I've decided to give myself permission to make the stat effects non-symmetric .  Stat =3 is now only a -1 mod, whereas stat=11 is still a +2 mod. Plus, I've added a 9 stat to the +1 column.  With this arrangement, one gets a bonus vs penalty proportion of 13/7 or making a "good result" almost twice as likely as a bad one.  This is entirely because I do think that players need at least some edge... ;)   and possibly by having the +2 outnumber the -2 by 3:1 , they may just complain a bit less.
Stat     Mod
0-2       -2
3-4       -1
5-8        0
9-10  +1
11+     +2
 Comments ?

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