In D&D, the rules describe how skill checks are made, and there is a chart for difficulty levels. The rules are primarily written in the context of individual skill checks, in which one character makes a skill check for his or her own benefit (or as part of a skill challenge, but I’m talking about non-challenge skill checks here). In practice, I find that for most noncombat skill checks, only one player needs to successfully make the check in order to benefit the entire party. This is what I call a “group skill check”. I find it useful to distinguish this kind of skill check from the individual skill check. And since there seem to be multiple ways GM’s might use to handle this situation, I thought it would be interesting to lay out the way I personally find best for handling this sort of check. This is organized and simplified from my blog article
part 1 and
part 2.
The method I have chosen is to have every player make a single skill check against the DC of the group skill check, and if any player succeeds in the skill check, the party succeeds in the skill check. The typical DC is 20 for a level 1 check. Here are the reasons I chose this method:
1. I decided I wanted having skills to be very useful even if you don't have the highest skill level in the party. In many games I've played, having a skill is pretty much useless if someone else in the party has a higher skill level than you. This isn't much fun if you are the one with the second-best skill. This is especially so in D&D, now that the party will have more total skills than the total number of skills in the game, so some of the skills will definitely be doubled up. Also, in D&D you basically have no control over how good you are in a skill unless you take rare feats like skill focus; if you take a skill, your ability in that skill depends on your statistics, and your statistics depend on your class. It is already not very efficient for a fighter to take a skill he won't be very good in, like Streetwise; why compound the problem by guaranteeing the skill won't be useful if the party has a higher charisma character who has taken the skill. Hence, I did not want to allow only the highest skill character to try the check.
2. Also, when I first saw the rules, I noticed that the bonus for training in a skill is rather small compared to what you would expect in reality or fiction. If the check is so hard that you have only at 50% chance of succeeding even with training, you still have a 25% chance of succeeding even without training. I decided that this is part of the “fun is better than simulation” aspect of the new D&D rules, and wanted to reflect this spirit in the use of my rules by allowing everyone to participate in the skill check, allowing the barbarian to occasionally get lucky and know more about arcane knowledge than the wizard.
3. The game has rules for “aid another”, but I decided not to use those rules. First, I don’t like the fact that the DC is fixed, meaning that once you reach a certain level the aid action becomes automatic and your level of skill no longer means anything at all - an incompetent helps just as much as an expert. This is a minor quibble because it could easily be fixed by setting the aid DC to equal (skill check DC – 10). My real objection is that even if you do this, the skill level of the aiding players has a rather small effect; the skill bonus of the lead player is 10x as important as that of anyone else.
4. In some campaigns, only characters who declare that they are trying the skill get to roll. But if I'm going to allow every character to make a skill roll, I think it is much more fair to simply have everyone do so rather than give bonuses to players who talk more.
5. I don’t use or allow passive skill checks for group skill checks. Passive skill checks guarantee that nothing matters except the character with the highest skill, and I am trying to avoid that. And I find that rolling dice is more fun for the players.
6. DC 20 gives the average party about a 70% chance of making the roll (see my math below), and I like making the characters successful more often than they are unsuccessful. And this isn't one of these "by average difficulty I mean easy" averages, this is an average difficulty. Characters are certainly highly successful in combat, they should have a good shot in noncombat too. I never understood games where any task interesting enough that a hero would want to do it, is so hard he has about a 25% chance of success. That just isn't a lot of fun.
7. DC 20 is also a nice number because it means that checks are generally not impossible, a one point difference in your skill almost always makes a difference. A skill bonus of 0 is better than a bonus of -1 and worse than a bonus of +1. This wouldn't be the case with DC 24, since the roll would be impossible in all 3 cases.
A more specific DC chart:
Characters should almost always succeed: DC 16
Characters should usually succeed: DC 18
Characters should succeed more often than not: DC 20
Character success is 50/50: DC 22
Characters should fail more often than not: DC 24
Characters should usually fail: DC 26
Characters should almost always fail: DC 28
Note that physical skills are slightly harder if the characters are wearing armor, so you may want to make them one point easier. Also note that “trained-only” checks are more difficult for the party to succeed at, so you would want to make them around 4 points easier.
These rules are appropriate for checks in which success by one player is just as good as success by everyone, and there is no cost for trying or penalty for failure. Here are some examples of group skill checks:
Knowledge checks (Arcana, Dungeoneering, History, Nature, Religion, Streetwise) are almost always group skill checks.
Noncombat Perception and Insight checks to see if the group notices something.
Thievery checks to see if the party can, for instance, open a locked door.
I also like to use it for social skill checks (Bluff, Diplomacy, Intimidate). While you might argue that it is more appropriate for one diplomat to make all the rolls while everyone else stays quiet, I prefer to be a bit more abstract and allow everyone to contribute. I imagine that the charismatic types are contributing more, but the better everyone is at social skills, the more chance the party as a whole has of succeeding. You might imagine, for instance, that the “special effect” of the surly dwarf succeeding in a group diplomacy roll, is that he managed to refrain from saying something rude that would have ruined the negotiations.
These numbers are meant to work well at heroic levels. At high levels group skill checks won’t work out quite the same as far as allowing the whole group to participate effectively, because the disparity between the skill levels of the party increase with level. But that’s just the way the D&D rules work.
The
DMG suggests increasing the DC of the average skill check by 2/3 per level. This may be appropriate when using skill based on your best stats, but for a group skill check where everyone participates, it seems a bit harsh. I’d suggest +0.6 per level.
Some notes on other types of skill checks:
The type of “group skill check” in which each person succeeds or fails separately (such as “everyone roll an Endurance check or lose a healing surge”) is straightforward and easy to do. The only thing to remember is that such a check is much, much harder than a group check. DC 10 would be about equivalent to the DC 20 group skill check I described above.
Skill checks in which everyone has to succeed – in which only the worst performance counts – are a totally different animal that is tricky to handle in a fun manner. I have a different system for this (see my blog article).
The system doesn’t envision “opposed” skill checks, as I’ve been using it for skill checks baked into a scenario. Personally, I don’t normally roll the monsters off against the players, I just set a difficulty for the players. This puts more control into the rolls of the player (all that rolling for the monster does is make the difficulty number for the players unpredictable, so sometimes the party fails with a good roll or succeeds with a bad roll). If I’m making the scenario, I don’t really need to look at the stats of the monsters, I just set the difficulty based on the situation. If you need to make an impromptu check, a DC of 12 + monster skill bonus seems reasonable if you want to players to succeed more often than not, the equivalent of a DC 20 group skill check.
Skill challenges are a totally different animal I’m not addressing here. But it seems to me that using a group skill check as one step of a challenge would work well, as long as you recognize that a step involving a group skill check has to have a higher DC than one requiring an individual skill check.
Mathematics:
The math behind choosing DC20: First we ask, what is the average skill bonus of a L1 character? If an L1 character has stats 18, 16, 13, 12, 11, 10 (after racial bonuses), the average stat bonus is +1.5. The average character class has 4 skills, but some characters may have feats or classes that give more, so assume 4.25 skills, which is ¼ of the total number of skills. This gives an average skill bonus of +1.25. And the average race has +2 in two skills, an average of +0.25 per skill. This gives an average skill bonus of +3.
How this is divided among the party will vary, but let’s assume +8, +5, +2, +0, +0. This means the chance of no one making a DC 20 check is 55% x 70% x 85% x 95% x 95% = 30%, so the chance of success is 70%.
The math behind the rate of skill progression: You get +1 every 2 levels just from the level bonus. You gain 11 points of statistics every 10 levels, which is about +1 to every skill for every 10 levels. Looking at the book, I see that most of the feats and utility powers than improve skill checks are low-level, more like something to factor into the basic numbers than something you gain with levels. You certainly can gain skill bonus magic items with levels – but you probably only are wearing about 1 even at the highest level. So whether you get a lot of bonuses at high level depends on whether your game encourages your high-level characters to buy hordes of cheap magic items and swap them about before performing each check. If not, you probably won’t gain even as much as +1 in every skill by 30th level.
You will, however, become more polarized – better in your best skills compared to your other skills. This is statistically advantageous. So if your party’s bonuses in a skill are +29/+23/+18/+16/+16 at 30th level, your chance of failing against DC 38 is (40% x 70% x 95%) = 27%, pretty close to the same. This works out to increasing the difficulty by 0.6 per level.
__________________
Come read my game design/analysis blog at:
http://gamedesignfanatic.blogspot.com
Gamers Online Now: 1,299
Linear Mode
