Friday, 20 January 2012

Mechanics of Attack Bonus progression in D&D and Heroes Against Darkness

One of the areas of D&D that has changed in most editions is the way that the game deals with the gradual improvements to a character's abilities over time. Each of the editions has some mechanism to reflect each character's skill improvement as they gain levels. In the earliest editions, this is achieved through predefined tables, whereas 4th edition (and Heroes Against Darkness), the improvement is calculated by summing inherent character properties (½ Level Bonus, Ability Score modifiers, weapon or magic modifiers).

+1 Per Level Through the Ages

Let's take a tour through the editions to see how each of them achieved the +1 per level progression:

• Character Hit Roll tables that progressively adjust the predefined number that must be rolled to hit a specific Armor Class

2nd Edition:
• Calculated THAC0 (To Hit Armor Class 0) tables, only defining the roll needed to hit a 0 Armor Class, with the player left to work out the actual target number for the dice roll for the monster's AC

3rd Edition:
• Base Attack Bonus (BAB), which increases (for fighters) at +1 per level, progressively slower for other classes
• Ability score increases (to a single score) at 4th, 8th, 12th, 16th Level (etc.)

4th Edition:
• Calculated Attack Bonus, which is the sum of Ability Score Modifier + ½ Level + Modifiers.
• Ability score increases (to a single score) at 4th, 8th, 12th, 16th Level (etc.)

Heroes Against Darkness:
• Calculated Melee Bonus and Ranged bonus, which is the sum of ½ Level + Ability Score Modifier + Modifiers.
• Ability score increases to two different scores at 3rd, 5th, 7th, 9th, 11th Level (etc.)

Components of +1 Per Level

In my previous post about the mechanics of 5th Edition, I fully broke down the attack bonus progression for 4th Edition and Heroes Against Darkness:

Dungeons and Dragons 4th Edition has the following underlying ingredients to achieve the +1 per level progression:
• ½ Level Bonus
• Weapon or magic enhancement every 5th level (assumed +1 weapon at level 5, +2 at level 10, etc)
• Ability score modifier increase every 7th or 8th level (via +1 to two ability scores every 4th level and then semi-randomly after that)
• Various feats and proficiencies that are available to the player, but are sometimes not chosen

If you add up the first three of these, you end up with a progression of about +0.85 per level, with the remainder (+0.15) coming from various feats. The 4th Edition feats that are used to plug these gaps include:
• Weapon Focus
• Weapon Talent
• Weapon/Implement Expertise

Heroes Against Darkness has the following components in its progression:
• ½ Level Bonus
• Improved weapon or magic enhancement every 4th level (assumed +1 weapon at level 4, +2 at level 8, etc)
• Ability score modifier increase every 4th level (via +1 to two ability scores every 2nd level starting at level 3)

Analysis of +1 Per Level Progression

The major difference between the earliest editions of D&D and 'modern' editions like 4th and Heroes Against Darkness is that the modern editions take into account more factors when calculating the +1 per level progression, such as magic weapons or other sundry equipment.

From Basic to the 3rd Edition of D&D, the progression does not factor in any magic weapons that the characters have. 4th edition and Heroes Against Darkness offer DMs guidance for when players are expected to earn better weapons and enhancements (with the obvious ability for GMs to accelerate or slow the distribution of these items).

From a mechanical point of view, the major difference between the two options is that in the early editions, there's no expected progression, so characters of the same level in different games may have vastly different attack bonuses, depending on the generosity or stinginess of their respective GMs.

For the modern game (4th Edition and Heroes Against Darkness) there are similarities and differences. Both systems employ the ½ Level bonus, but Heroes Against Darkness offers more frequent ability score modifier increases (every 4th level) and improved weapon or magic enhancement bonuses (also every 4th level, but staggered) to compensate for not having feats with mechanical bonuses.

In combination, Heroes Against Darkness' three elements add up to +1 per level, like this:

Level 2: ½ Level Bonus increases (+1)
Level 3: Characters find improved weapon or magic enhancement (+1)
Level 4: ½ Level Bonus increases (+1)
Level 5: Player increases primary Ability Score to an even number (+1)
...and so on...

The difference here underscores the characteristics and emphasis of each of the games. 4th Edition, like 3rd before it, is a game which offers players lots of character build choices of feats and powers. Heroes Against Darkness doesn't offer character build choices for feats and powers, instead predefining the powers for each class to keep the game simple and streamlined.

Advantages of Calculated +1 Per Level Progression

As I see it, the advantage of a modern calculated +1 per level progression is that it can apply to more than just melee attacks.

For example, in Heroes Against Darkness, I use calculated bonuses for each of the types of attacks in the game:
Melee Bonus: Strength Bonus + ½ Level Bonus + Modifiers
Ranged Bonus: Dexterity Bonus + ½ Level Bonus + Modifiers
Magic Bonus: Wisdom Bonus + ½ Level Bonus + Modifiers

The progression of these is inherent in the rules and reward systems.

For Hunters, their Ranged Bonus will increase at +1 per level because the player will likely increase his character's Dexterity Score by +1 every second level and the GM will likely grant that player an improved ranged weapon as treasure at appropriate points in the campaign (approximately every 4th level). This same progression applies to each of the classes, where the player will increase their character's most important Ability Score every 2nd level, and the GM will reward the players with improved weapons or magic enhancements approximately every 4th level.

Furthermore, because there are no feats or power choices, there are no bad decisions that the players can make, such as not choosing the right feats (such as the essential feat taxes) or the ideal powers for their class (or race).

Grab the Alpha version from the downloads page to see for yourself whether it's succeeded: Heroes Against Darkness.


  1. Good analysis. A lot of us seem to be pondering this facet of D&D these days.

  2. Hmm, makes me wonder why we even still have the basic flat +x enhancement bonus to magic weapons. Maybe just go ahead and give everyone +1 per level flat out, and magic weapons could have some other properties.

    1. Hey Jay. D&D Dark Sun has used a flat +1 per level, and D&D Next is moving away from +X weapons and towards weapons with special features (such as +d6 cold damage once per day).