Tuesday, May 3, 2016

A Different Type of "Skill Check"

I'm sure I've posted the following excerpt in the past, but I can't be bothered to find it at the moment, so here it is again:

"SAVING VS. ABILITIES (OPTIONAL): The DM may want to base a character's chance of doing something on his or her ability ratings (Strength, etc.). The player must roll the ability rating or less on a d20. The DM may give a bonus or penalty to the roll, depending on the difficulty of the action (-4 for a simple task, +4 for a difficult one, etc.). It is suggested that a roll of 1 always succeed and a roll of 20 always fail."

- From the 1981 D&D Expert Set, page X51

A simple enough rule, and one that I've used on many occasions running B/X; it is the basis for the BECMI skills first presented in the various Mystara "gazetteers" and later in the Rules Cyclopedia.

[these, by the way, worked pretty much the same as the AD&D "non-weapon proficiencies" (first presented in Oriental Adventures, a book mainly written by the same guy: Zeb Cook), and exactly the same as Cook's 2nd Edition AD&D non-weapon proficiencies...all of which I hate, by the way]

I never much cared for the BECMI skills (even when I liked BECMI), and these days I'm not even a fan of the "roll under ability" rule. Simple as it is, when I look back on the way I've used it in the past, I find myself shuddering a bit.

Why? Because I used it as a catchall guideline rule for determining whether or not a PC could execute a particular plan or out-of-the-box action effectively, rather than presuming character competence. It's an antithetical approach to my current philosophy of D&D play.

But aside from any "philosophical" issues, as a form of micro-managing character action it leads to a higher rate of character incompetence, which is less fun for everyone involved. Consider one of the classic challenges of AD&D: the suspended disks acting as a "trail" over boiling mud from White Plume Mountain. A standard method of getting across the cavern (for those who aren't able to fly) is to make a series of jumps from disk-to-disk, using a "roll-under-ability" for success. Certainly, that's what I've always done in the past.

[don't laugh]

Here's the problem: with a check of this type, a series of task rolls reduces one's chance of success exponentially. Consider the guy with a DEX of 16...an 80% chance to make the jump to a disk is pretty good, right? Sure...but having to make all nine jumps (there are nine disks in the cavern) means that the cumulative chance of success is only 13%. It's a bit better if (like me) your DM allowed a "reroll" attempt on a miss (a second DEX check to see if the PC can "catch herself") but even then it's no better than a 4-in-6 chance of overall success...and less if the guy has to roll to make it from the last disk to the opposite ledge (a 10th jump). And THAT for a PC with DEX 16...what about the shlub who only has DEX 10?

"Aiieeee! It burns! It burns!"
[by the way, even 3E's alternate skill system runs into this issue in their version of WPM, requiring a jump skill check of 14 for every single disk. Fine and dandy for 7th level PCs who've maxed out their jump and have an 18 DEX (the average L7 thief in 3E)...but what about the guys who didn't put points into jump? Multiply their success chance against itself ten times to see what they're REAL chance of navigating the challenge is!]

Of course, there's more to complain about than just this. Binary (yes/no, success/fail) systems lack any kind of grey-area gradient. There's no room for partial success (nor partial failure), which can curb the irritation at "whiffing completely" while still preserving the old school integrity of character's NOT always failing up just because they're (story) "protagonists."

Thus enter Steve C's rather brilliant idea of repurposing the standard B/X reaction table to account for more than simply whether or not a wandering subterranean denizen wants to take your head as a trophy for its mate. Steve's idea was to use the table to expedite all manner of random issues that might come up in game, rather than spend time searching for obscure systems or hemming-&-hawing over how to rule certain situations...things that other DM's might determine with a simple coin flip (the ultimate binary test) could instead have a non-binary gradient to it.

For folks unfamiliar with the reaction table, it's a 2D6 roll which can be modified by a CHA adjustment (max of +/- two, and usually no more than one point) or circumstance (again, usually by no more than a point or two). The table results break down like this:

2 or less: Immediate attack
3 to 5: Hostile reaction
6 to 8: Uncertain, confusion (roll again)
9 to 11: No attack, leaves or considers offer
12: Enthusiastic friendship

[I realize that this table originally appeared in Might & Magic (OD&D), but Steve's use of an ability score adjustment is what leads me to presume he's taking it from B/X, seeing as how neither OD&D nor Holmes offered specific ability-based (CHA) adjustment to reaction checks...and Moldvay did]

Steve runs with this, giving a simple five-result table ranging from "catastrophically bad" to "extremely good" as a way of judging all those little things that crop up in a game. I say, hell, let's take it a step further and use it to resolve all those "ability saves" in a non-binary fashion!

Take the White Plume Mountain example. Rather than force players to make a series of jumping rolls, why not have them make a single roll (modified by DEX) to see how well they navigate the challenge?

2D6 (modified by DEX initiative adjustment):
2 or less: mistimes jump, plummets into mud (take damage from fall and boiling mud, as usual)
3 to 5: nearly slips but manages to grasp edge of disk though being completely dowsed by muddy geyser (take damage and al further checks to navigate disks are made at -2 penalty).
6 to 8: holds up on disk just in time as a geyser blows (take moderate damage; roll again to continue with cumulative +1 bonus)
9 to 11: made it across! only light damage taken from geyser splatters
12 or more: what a show! made it across without being splashed (and damaged) by boiling mud.

Nice, huh? So much simpler and quicker to resolve than a series of tests, and with an easy range of possible outcomes. Using the reaction table as a base, many "ability challenges" can be resolved in this way, with tastier results than binary systems, and little-to-no need for any kit-bashed skills system.

Some folks may object to such a simplified system of task resolution, saying it doesn't take into account character experience...shouldn't a 6th level character (for example) be better at such a task than a 3rd level character? To those folks I say: HUH? What in a character's class training has taught her how to navigate some mad wizard's bizarre challenge? Why would "experience" count for any such thing?

This isn't a "skill" in which a character trains (like fighting and thieving and spell-casting)...nor is it something that falls into a character's presumed sphere of competence (like knowing how to build a fire or how to tie a good knot or how to mend her basic equipment). We're talking about strange situations, outside the ordinary things encountered...things where the "save versus ability" roll has (in the past) been the main explicit option. Even if a character HAS done the "jumping disk" thing in a past adventure, chances are she hasn't been prepping every weekend since, like some fitness nut training for the American Ninja Warrior competition.

No...success or failure at these kinds of challenges need a system that shows the virtual crapshoot of attempting it (i.e. via random roll), possibly modified by native talent, possibly modified by other DM-arbitrated adjustments (as with reaction rolls). And in such cases, I think it's fair to have a range of possible consequences, only the worst of which is "abject failure."

This is something I'll be throwing into my future games...assuming I ever get back to the gaming table. Thanks for this, Steve!
: )


  1. This is the core mechanic of the popular apocalypse world indie game engine. The greatest tools were there all along, we were all to foolish too see them.

    1. @ HeyJ:

      Huh. Still haven't gotten around to picking up the AW books. One of these days...

  2. I like your riffing on the subject, JB!

    I think you're right. The genesis of my thinking was definitely the B/X and Holmes Reaction tables. My thinking for "ability modifier" was the +1/-1 from S&W WhiteBox, as that's my current preferred ruleset.

    Thanks for the shoutout, much appreciated!

  3. Funny. I was thinking about the white plume mt area yesterday. Now I'm going to have to post about this.

    1. @ Darn:

      I'm always interested in reading others' WPM thoughts.
      ; )

  4. Adapting the reaction table to be a moree general task resolution system is a good idea that was curiously missed or ignored for years.
    I've used it and it works like a charm. It's easy to adapt by skill or level by giving some sort of threshold, anyyone better gets a bbonus, anyone worse gets a penalty with one or to points being all you need to alter results.

    1. @ JDJ:

      One more example of me being late to the party. Sorry I didn't see this earlier!

    2. No, great minds, great minds.

  5. Excellent post, good system. I do think that there's a place for high risk solutions like the 'DEX check alone' mud trap - when the solurion is a bad one, as it is with jumping disk to disk.

    Telling the players the risk is the key there, because one has to let them make bad decisions.

    Also ability checks v. skill comes into play. With the mud disks one might make all PCs without climb/acrobatics leap across, check by check, but for the thief say - one climb check (and as usually with skill failures) missing it means being stuck or prevented from suceeding rather then the nebbish's catastrophic failure.

  6. This is really cool! The recent Doctor Who RPG uses 2d6 with a similar table for almost all actions; the results mean that even good results can have a bad side effect if they're cutting it close, and vice versa.

    I'll certainly be looking to adapt this to situations in my own campaign, since it's looking like I'll be switching to either B/X or Basic Fantasy in the near future.

  7. Speaking of Basic Fantasy, they have a chart for ability checks that does take level into account. It is just a target number for a d20 roll though.

  8. Great post! I think 2d6 for everything is not only functional and awesome, but also "the" original method of doing things.

    Rolling for each single jump is indeed a bad idea; I am not the greatest fan of Burning Wheel, but it has a nice rules that basically states that if circumstances haven't changed, you only roll once.

    Here is one take on using 2d6 for everything, BTW:

    I would avoid ignoring level, to be honest, because level is actually more important than abilities in OS play, the way I see it; on the other hand, I let players increase abilites as they level up, so it might work.

    1. @ Eric:

      I agree that level is (or should be) more important than ability scores, but...for me...I would not apply it to ALL aspects of a character, only "skills" related to the character's profession.

      I don't give a bonus to reaction rolls, for example...why would I give it to a fighter's chance to climb a crumbling cliff face? Because "climbing cliffs" is part of the adventuring profession? No more so than conversing with the encountered denizens of the underworld! No, it's outside the fighter's area of expertise and training (i.e. fighting). SO: no bonus for either.

      Otherwise, I'm just trading one fiddly "skill system" for a slightly less fiddly one.
      ; )

    2. Yeah, that works too. It feels closer to LotFP somewhat, which is a bit less fiddly than most skill systems.

      I actually stopped playing GURPS because of the skill system - same reason I wont play 3e, Burning Wheel, etc.

      I prefer simple skills as well! :)

  9. Seriously, have a look at Dungeon World. You've effectively arrived at their solution here.

    1. @ Jack:

      I'll check it out at some point.

    2. Well, I would say that Dungeon World (and AW before that) is heavily based upon the 2d6 target resolution that came from RC, Moldvay, and OD&D before that. Basically, just apply the reaction table to everything.

      Since DW is free and cool (but not too old school IMO), its worth checking out anyway.

  10. If you DID want to take experience into consideration, you could tweak the numbers a bit and steal a page from C&C and 5e. Add +1 for every 2 levels of exp if the situation (or the player's approach) uses a prime requisite ability, +1 for every 4 levels if not. But yeah, it's an interesting idea.

  11. I adopted Talislanta's task resolution system for BX "Skills" years ago, and it's the same thing as what you've described, except you roll a D20. It never occurred to me to take and modify the reaction table, though it is essentially the same thing. Hindsight is 20/20 I guess.

    1. @ Dieter:

      Huh...Talislanta isn't a system I've ever owned/read. But it would seem to me that a D20 system would NOT be the same, as the bell curve of probability is very different from a 2D6 system (though I suppose it could be weighted).

      Or maybe your reply was to Tom's comment...?

    2. Nope, it was to your comment :)

      Tal uses a table, with 5 levels of success:
      0 or less: Critical Failure
      1-5: Failure
      6-10: Partial Success
      11-19: Success
      20 or more: Critical Success

      All actions in the game are resolved by rolling a D20, and applying appropriate modifiers, penalties or bonuses (+1 for Strength, etc.).

      Yes, you are right, a D20 is not a bell-curve, I didn;t mean to imply that it was.
      I was commenting on the similar idea of using the table, with 5 levels of success, to resolve skill checks.

      You should check out Tal. It's a neat system, and qualifies as "old-school" (the 1st edition came out in 1981 if I recall correctly).

      The owner of the game made all the material, for all 5 editions, free in PDF format at talislanta.com

    3. @ Dieter:

      Awesome! Thanks for the info...I'll be sure to check it out.