Tag Archives: Rules Compendium

Two Problems that Provoked Bounded Accuracy

One of the key design features of D&D Next is something the designers call bounded accuracy. Bounded accuracy reins in the steady escalation of bonuses to checks and attacks that characters received in earlier editions. I love bounded accuracy.

To explain my affection, I want to consider two problems with (nearly) unbounded accuracy in the third and fourth edition.

Third and fourth edition both assumed a steep and steady increase of plusses to your skill numbers as your character advanced. This rewarded you with a sense of accomplishment as you saw your character improve, but the increases led to problems at higher levels.

In third edition, at each level, characters received an allotment of points to improve selected skills. If you reached high level, and concentrated your improvements on the same skills, you gained huge bonuses to those skills.

The huge bonuses created a dilemma for dungeon masters and authors trying to set DCs for high level adventures. You could set very high DCs that challenged players who specialized in a skill. These DCs were impossibly high for non-specialists, so if the party lacked a specialist in a particular skill, the task became flat out impossible. Alternately, you could set low enough DCs to give non-specialists a chance, but these DCs grant the specialists an automatic success.  (Again, by specialists, I just mean a character who concentrates skill improvements on the same skill, not a super-optimized character.)

Third edition assumes that the DM will justify the sky-high DCs required to challenge high-level specialists by describing obstacles of legendary proportions. At first level, the rogue must climb a rough dungeon wall; by 20th level, he must climb a glass-smooth wall covered in wet slime—in an earthquake. At first level, you must negotiate with the mayor; by twentieth level, he’s king. And you killed his dog.

In the skill section of the third edition Epic Level Handbook, the epic-level obstacles become absurd. Here we find the DC for balancing on clouds, sweet talking hostile creatures into sacrificing their lives for you, and so on. I understand that some folks enjoy playing characters as mythic, godlike creatures, but to me, that game doesn’t seem like D&D anymore. Given the rarity of epic play, I suspect I stand with the majority.

Fourth edition tried to resolve the problem of high-level DCs becoming either impossible for typical characters or automatic for specialists. The system grants every character a flat, half-level bonus to checks. Now skilled characters maintained a flat +5 bonus when compared to their peers. Everyone enjoyed steady increases, but no one fell too far behind. This approach fixed the math, but when you compare characters of different levels, it defies logic and breaks your suspension of disbelief.

By level 10, a wizard with an 8 strength, gains the same ability to smash down a wooden door as an first-level character with an 18 strength.

“Wow, Wiz, have you been working out?”

“Thanks for noticing. My strength will be 9 soon.”

Of course, Wiz never gets a chance to show off his new prowess, because those DC 16 wooden doors have all been replaced by level-appropriate, DC 20 barred doors.

In truth, the players never really advance because they stand on a treadmill.

You can see the treadmill on page 126 of the 4e Rules Compendium in the “Difficulty Class By Level” table. Using this table, your character no longer gets better at easy checks, she just faces higher DCs. That table makes Living Forgotten Realms adventures work across entire tiers.

Fourth edition is inconsistent about whether the rising DCs in the “Difficulty Class By Level” table represent increasingly legendary barriers in the game world. For example, the DCs for breaking doors rise as the doors become sturdier. But social skills tend to be pegged to the DC-by-level table. (The system just assumes you killed the king’s dog.) The Living Forgotten Realms adventures used for organized play mostly abandon any attempt to flavor the rising DCs as increasingly legendary challenges. The challenges never change, just the DCs.

By reining in the scale of skill bonuses as character’s advance, D&D Next solves both problems. The system does not reward players with the same magnitude of improvements as their character’s advances, but the small improvements are real improvements, not steps on a treadmill.

While bounded accuracy solves problems, characters still need to stand out from their peers. A specialist should stand out and enjoy a chance to shine. The current ability bonuses are too small to achieve this. You can read my opinion on ability bonuses and checks here.