... now with 35% more arrogance!

Tuesday, July 19, 2011

Target Numbers

Lots of discussion going on about the latest Mike Mearls article on WotC's site, which many people are interpreting as a sneak preview to 5e. I'm not going to go into that; instead, I want to focus on his description of an ability check mechanic:
"Ability checks with a d20 measured against a DC serve as the basic rule."
I think that's a lousy way to handle ability checks. You have two different things varying: the ability and the DC (plus the die roll, but that's a given.) That's not even counting additional modifiers; we're just talking about the minimum needed for the core mechanic. And it gets worse, because it's obvious in the article he's talking about ability check based on ability modifiers: roll or point-buy your abilities, look them up on a table to get your modifier, add this to your die roll, and look up the target number of the task you're trying to accomplish. That's a whole lot of extra work.

Really, you only need one thing to vary, so you have two options:
  1. Make the DC equal to the ability (roll under system.) This ditches ability score bonuses except as situational modifiers or bonuses to other things, like damage. Super simple.
  2. Make the DC equal to the opponent's ability (roll over system.) If there is no opponent, use a fixed number. Target 20 does the fixed target straight across, Epées & Sorcellerie uses AC or Dex of the opponent as a target, but there are other possible variants.
Since Mearls, as a WotC employee, is dedicated to the d20 roll-over approach, he can't pick the first option, but doesn't want to commit fully to the second option to truly simplify D&D. What I'd do, if I wanted his approach, would be:

(EDIT: I screwed this part up the first time. TWO different errors, and ironically it's because I made the same mistake I accused Mearls of making. Corrected now.)
  • Generate ability scores in the standard way (3d6 base, but those who want 7d6 drop four or standard array point-buy or whatever can do so.)
  • To attack or change/affect your opponent, roll d20. Result => opponent's appropriate ability score means success.
  • For saves against physical danger, add your own ability score to the d20 roll and beat target 20 (i.e. average character saves a little more than half the time.)
  • For class abilities, add level; for saves against spells, add opponent's level to target.
The trick to this is you never need to look up DCs in a rule book, unlike 3e+. It's all based on the character sheet or the GM's notes. Your target number is always either 20 or an opponent's ability score, plus appropriate modifiers.

Clever players can come up with ways to get a bonus from another ability; this is where ability modifiers come in. For example, a fighter could attack normally (d20 + level) or slam an opponent with a shield (as normal, but add Str mod.) Optionally, feats or skills would let you add such bonuses in specific situations: Anatomy skill might allow adding Int bonus to d20 attacks. Any feat or skill list would be suggestions only; players and GMs could churn out an unlimited number of these using this one simple rule.

(EDIT: Had to correct the examples, too, to match the corrected rules.)


  1. Wait a second, but I'm totally confused: If your system is a d20+ability score >= opponent's ability score then that means that the actor succeeds automatically if their ability score itself is >= their opponent's ability score.

    E.g., a PC with a Strength of 9 performs some opposed Strength action against an opponent who also has a Strength of nine. The PC automatically succeeds since a d20+9 is always >= 9?

    Clearly I'm missing something.

  2. @bombshelter13: You aren't missing anything; I screwed it up and was correcting it while you were posting your comment. The problem is that it shouldn't be d20 + ability score. It's just d20 vs. opponent's ability score.

    I made the same mistake I complained about in the start of the post. I'm so ashamed.