Skills and the Paying of Bills

The chart of recommended DCs by level in 4e has been done three times- once in the original DMG on the famous page 42, changed in the DMG2, and changed still further in the D&D Rules Compendium. Basically, the designers had a hard time nailing down the math for skills. And it’s easy to see why. We’ve seen how “to hit” bonuses in combat were basically kept uniform across various characters- the game assumes a +5 bonus at 1st level and increases from there through various means. However, the bonuses on individual skills can go all over the place- anywhere from -2 to +13. On top of all this, skill challenges, a noble attempt to provide some mechanical support to out of combat activities, were presented in an embryonic form and required some tweaking. There’s room for improvement, meaning the question is both how skills work in 4e and how they ought to work.

A Storm of Status Effects

Status effects are where a lot of the potential nightmare lies in retrocloning 4e. They make up most of what makes attack powers unique, there are a hell of a lot of them (16 in total), there’s no clear ranking of what’s more powerful and by how much, and pretty much none of them are identical to the named effects in the 3rd edition SRD. This means that you have to come up with the wording yourself and avoid replicating what’s in the rulebooks.

A Game of Roles

Roles are a little misunderstood. Like English grammar, they tend to be more descriptive than prescriptive- they don’t strictly limit a PC’s behavior in combat by themselves. Rather, they sum up the total effects of a PC’s class features and powers, which are focused on- but never strictly limited to- certain patterns. This is where 4e gives you room to have classes that serve the same general role but play in different ways, as well as encourage different builds within a class. A Defender is never just a Defender, a Striker is never just a Striker, etc. 

But if we’re looking to build classes and powers, what are the roles giving us in game mechanical terms? 

Anatomy of A Power

Powers are the most widely-recognized feature of 4th Edition; the At-Will, Encounter, Daily, Utility structure (AEDU) is both criticized for its “homogenization” of classes (though they each use the structure to do different things) and praised for giving a clear structure to balance their abilities. One Level 3 Encounter Power is, in theory, as good as any other.

Powers are also the biggest challenge for anyone trying to do a clone of 4th edition. Their sheer quantity is overwhelming, and going along with it, the game never really told us how to create our own. (Had the line lasted until a DMG 3, perhaps this would have happened. Perhaps.) It’s something that appears to never have been an exact science- there’s no fixed formula weighing different aspects- but we can both find patterns in the process and hopefully refine it. 

Finishing up Assumptions: Monster Durability

Just filling in the gaps on what we’ve learned so far. We’ve looked at how often the PCs are assumed to hit the monsters (a little over half the time), and how much they can take from the monsters, so the question is how many hits are the monsters built to take?

Yes, But How Tough Are They?- The Second Assumption

Let’s look at the other half of the equation for a second- that being, how often are the PCs getting hit, and how much can they take before going down? Here the system varies a bit more, but we can still see a few assumptions.

A level 1 monster has, per the MM3 math, a +6 to-hit bonus. However, PC Armor Class gets a lot more varied by level. Let’s consider the high end of the spectrum: a 1st-level fighter armored in plate and heavy shield has a total AC of 20, requiring the monster roll a 14 or better- hitting 30% of the time. A wizard with a 16 intelligence gets to add that to their AC, so while they have no armor, they have an effective AC of 13, requiring a roll of 7 or better. A Warlock who only makes Intelligence a 10 (against the advice of the PHB, mind you, which makes it a secondary score for both suggested builds) would be able to wear leather armor for a +2, so I think it’s fair to say that 12 is the lower end, requiring the DM roll a 6 or better, or rather, hitting 70% of the time. Take the low chance (30%) and the high chance (70%), average them out, and-

Monsters hit the PCs about half the time, varying depending on which they attack.

That latter bit of the equation is very important, because 4th Edition combat is very much about tactics. The better-armored Defender types have mechanics (usually marks) which force the DM, playing as the monsters, to make the choice whether to attack them and struggle uphill, or attack a more vulnerable character and be more likely to deal damage, but also suffer consequences. This means, given the first assumption, that monsters are about 5% less accurate than the PCs, but this can be obviated the larger an encounter group is. 

Again, the players have some mechanics they can manipulate to help themselves out- making choices between armor that offers more protection but incurs check penalties, using powers that buff AC, etc. Monsters that attack the non-AC defenses are more likely to score a hit, which means players have to get cautious whenever they see a goblin wizard take the field. (And by cautious I mean “kill the handwavey one first!”) 

The average damage done by a level 1 monster is 9 points. (This is similar to the famous Page 42 table and its revised equivalent on page 65 of the DMG 2, where the average for Medium “Normal Damage Expressions” for levels 1-3 is 8.5.)

PC hit points vary by class and Consitution score, which is used in total (rather than as a modifier). At the low end, a Wizard who neglects Constitution may end up with 18 hit points at first level, while a fighter will be closer to 29 or 27 unless they really max out their Con. The wizard will fall after two average blows, the fighter after three or more. 

So, starting characters can take up to two or three hits before falling.

In some ways this is the most radical change 4th Edition makes to its take on Dungeons and Dragons. 1st level PCs in early versions of D&D were notoriously fragile, risking being cut down in one hit from a lucky roll by a wily kobold. This tied into an assumed play style of cautious exploration and strategic infiltration- at early levels, straight up fights with the enemy were to be avoided, and ambushes and traps were the way to defeat opposing forces, if you had to fight them at all. Experience points gained from treasure far outpaced anything you got from defeating enemies, so low-level D&D was something like a heist; sneak into the Tomb of the Last Dragon King, steal the riches therein (taking care to find the Amulet of Infinity which is worth more than everything else in the vault combined), and try not to alert the ghouls skulking about. 

This is, let’s be perfectly clear, a valid and fun playstyle, and developing a version of 4e that better supports it might be a fun project for cloners to do. 4th Edition is perhaps aimed most at those who saw the cover of the Mentzer Basic Set with its picture of a fighter facing down a red dragon with no care for strategic maneuvering and expected a game of heroic action fantasy. Sometimes you just want to be Big Damn Heroes and as far as I’m concerned no edition of the game does that playstyle better than 4th.

A word briefly on higher levels. Say our sickly wizard survives all the way to epic levels. At level 30 he’s looking at 18+ (29x4) HP, or 134 Hit Points. A level 30 monster is doing an average of 38 points of damage per hit. So the Wizard can take three solid hits from that monster before having to worry. Our more durable Fighter can take 7 or 8 hits. While high level combat has been known to drag a bit, the increase in PC survivability isn’t enough to make them untouchable. 

Not that our first level Wizard is sitting pretty with all 18 hit points and the ability to take one solid hit without dropping. Not being “one shotted” is all well and good but starting PCs still have to be cautious. Healing is more plentiful in 4e than in many other editions, but regulated by Healing Surges, which limit how often most healing abilities will be effective (those healing powers which DON’T spend healing surges are usually Daily powers.) Healing Surges model the attrition of healing ability which in prior editions was most often simply the Cleric’s number of spells per day, giving them more flexibility. (13th Age and the OGL Archmage engine reskin the concept as “Recoveries”.)

So with healing usually being available in an encounter, we can perhaps bump up the number of hits characters can take to three or four, if they ration wisely. Make no mistake- 4e combat is no foregone conclusion, and it asks good tactical thinking of the players. But by removing that risk of instantly being cut down by the first arrow of an enemy archer, 4e makes the PCs just a little bolder. 

The First Assumption

When I talk about an OGL 4e, I’m not talking about duplicating every power, class, and feat. That would be probably not legal, and pointless since Wizards of the Coast has made the 4e core rulebooks available for sale as PDFs and anyone who wants that game can get it. What I’m talking about is building a system that works in the same way. And the way to do that is to look at the core of how 4e works. 

Both fans and detractors of 4th Edition talk about it being balanced. This means a lot of things. The first is that two characters of the same level, regardless of their class, will be equally effective in play. It also means that both characters will get an opportunity to be effective in a given encounter.

The way it does this is by assuming that all characters of a certain level, regardless of class, race, etc., will have similar numbers for attack, defense, and so on. Note that I’m saying “similar” but not “identical”. There’s a range of numbers and certain variations between specific stats help differentiate between classes. But all this has been very vague. Let’s go to the first assumption.

1. A character of a given level will, when attacking a monster of the same level, hit on a roll of 10 or better before modifiers.

Consider the most important “fan created” bit of reverse engineering- “Monster Manual 3 on a business card”. The math used for MM3, the Monster Vault, and all subsequent material for the game makes it so that all monsters of a certain level will have a similar attack bonus, average damage, HP total, and AC, with room for variation based on the kind of monster it is.

By that time, monster generation got simple enough that over at Blog of Holding, someone bothered to write it up as a business card. It’s a useful little thing for any 4e DM wanting to do some homebrewing (or simply fix the monsters in earlier books) so go and get that. 

One of the rules of monster math is that AC equals 14 + the monster’s level. This means that a level 1 monster will usually have an AC of 15. “Soldier” monsters get a bonus of +2, brutes and 

artillery get a penalty of -2. The various monster blocks come up with different ways of getting to this total, combining actual armor the monster may have with Dex or Int bonuses. 

So Barbara the level 1 Fighter is attacking a level 1 monster. She needs the total on her attack roll to be 15 or better. The assumption, then, is that she has a +5 bonus to attack. Where does this come from?

There is no Base Attack Bonus or THAC0 in 4e. Rather your to-hit bonus comes from your ability score modifier, half your level, and proficiency in the weapon you use. Which ability score modifier is decided by what kind of attack it is- most melee attacks are based on Strength, ranged weapon attacks on Dexterity, and for magical classes it varies.

The first method of ability score generation in the PHB is the “standard array”, where the highest score, before any racial modifiers, is a 16. The description for each class tells you what your highest ability score should be. For Fighters, it’s Strength. So assuming you don’t make the “optimal” combination of race and class- let’s say Barbara here is a gnome fighter- you have a 16, and so a +3 mod, for the score you will be using most often to attack.

(You can aim for an 18, or even a 20 starting out if you match bonuses properly, but then it’s also possible to end up with a 14 so a 16-17 is a good midpoint.)

So Barbara uses one of her attack powers. From her stat she has a +3 bonus, and +0 from her level because you always round down. So that means she needs a 12 or better! But we’re not done yet.

Weapon proficiency acts as a bonus in 4e, not a penalty (though it could be argued the difference is mostly psychological.) If you use a weapon in which you are proficient, you get a bonus. Most of the weapons listed offer a bonus of +2, with the occasional +3. So most of the time you’ll be adding +2 to your attack total. So assuming Barbara uses a battleaxe, as she is wont to do, she has a total bonus to attack of +5. Which means to hit most level 1 monsters, she needs a 10 or better.

Now if Barbara switched to a weapon with a +3 bonus, she’d only need a 9 or better, but there are usually trade offs in damage, crit range, and so on. Let’s assume she really maxes out though, and gets a 20 Strength and has a sword with a +3 proficiency bonus- now she’s hitting on a 7 or better, an increase of 15%. “CharOp” players have found ways to rack up bonuses that are even higher! There’s clearly room for variance and optimization, but what’s important is the bottom end- someone who just follows the book’s advice to put a good score in their class’s primary attribute is going to do just fine. 

What about a Wizard firing a spell? They don’t get the proficiency bonus since they’re not using a weapon- but most spells don’t target AC, but one of the other defenses. Defenses are, on average, 2 lower. Hence the math is basically the same. This little quirk in the rules helps reinforce the idea that Wizards don’t rely on weapons or normal attacks, thus protecting the niche of the martial classes. (They even have their own equivalent of the +2/+3 choice, through finding superior implements to get a +1 bonus.)

Monster AC rises with level on a one-for-one basis, but PC attack bonuses rise in a number of different ways. The “half-level” rule means that you get another +1 every even level, and every four levels you get to boost an ability score- the game assumes you’ll put that in your class’s primary. (Sublesson here: the game rewards specialization!) The game as published also assumed that you would get magic items at a certain rate, but later products introduced the idea of substituting bonuses to attack, damage, AC, and other defenses by level, so that magic items could be eliminated, saved for rarer occasions, etc. Finally, after some complains that players seemed to lag slightly behind at higher levels, the game introduced Expertise bonuses which gave a bonus to damage and attack rolls. With all those accounted for (and many 4e DMs both use Inherent Bonuses and give the Expertise feat for free around 5th level or so), the players stay within that 10-or-better range.

To put it even more simply, the game assumes that PCs hit monsters around 55% of the time, but allows for some deviation from this rule in both directions. By letting players fiddle with their bonuses here and there, it gives them a part in making their characters good at what they do, and since the DM can throw monsters that are easier or harder to hit at them, the game never feels too predictable. 

I'm Hacking 4e And So Can You

Right now I’m working on a game which takes the framework of Dungeons & Dragons 4th Edition and places it into a space opera milieu. One of my reasons for undertaking this project was to find a way to legally do a retroclone of 4th Edition, an edition of D&D not released under the OGL. (A petition exists, if you're interested.) It’s closer to 4th than some similar games like Strike! or Rob Heinsoo and Jonathan Tweet’s own 13th Age, which both go in their own directions, but there are some significant differences. Inevitably trying to pay tribute to an edition which made some radical changes in the name of balance and consistency ends up with you making ever more changes in the name of balance and consistency. 

However, in the course of trying to tinker with 4e, I’ve learned a lot about how the system is built, and the underlying assumptions that make it work as well as it does. So while I work on Grand Well-Balanced Space Opera Project , I think the fastest way to actually make all this accessible to the OGL community is to share what I’ve found and talk about how it might be adapted for use in your own OGL stuff. Obviously you can’t just drop the 4e Fighter into a Pathfinder game and expect him to play the same, but you can, with effort, build something that works.

OGL Notice

All mechanical material on this blog is released as Open Game Content, as defined in the Open Gaming License version 1.0a section 1(d). All material published by me via Blogger under the Open Game License v. 1.0a Copyright 2000 by Wizards of the Coast, Inc.

Link to the Open Game License v. 1.0a.