D&D 4E Showing the Math: Proving that 4e’s Skill Challenge system is broken (math heavy)

[FadedC]

It's the footnote to the DC table on page 42. I didn't notice it at first, either.

Ah there it is. Ok so it seems like the general rule is that a trained character with an 18 stat should succeed at easy 75% of the time, medium 50% and hard 25%. This seems completely reasonable until you have skill challenges that require twice as many successes as failures.

A simple band aid fix would be to simply change the complexity rules. Require 4 successes before 4 failures and you should see average skill people completing their tasks half the time while those with extra skill bonuses will have a chance to shine.

 

[CSK]

The percent chance to get 2K successes before K failures with probability of success P is:

 \K  1    2    3    4    5
P \-------------------------
.05  0.2  0.0  0.0  0.0  0.0
.10  1.0  0.0  0.0  0.0  0.0
.15  2.2  0.2  0.0  0.0  0.0
.20  4.0  0.7  0.1  0.0  0.0
.25  6.2  1.6  0.4  0.1  0.0
.30  9.0  3.1  1.1  0.4  0.2
.35 12.2  5.4  2.5  1.2  0.6
.40 16.0  8.7  5.0  2.9  1.8
.45 20.2 13.1  8.8  6.1  4.3
.50 25.0 18.8 14.5 11.3  9.0
.55 30.2 25.6 22.0 19.1 16.7
.60 36.0 33.7 31.5 29.6 27.9
.65 42.2 42.8 42.8 42.6 42.3
.70 49.0 52.8 55.2 57.0 58.4
.75 56.2 63.3 67.9 71.3 74.2
.80 64.0 73.7 79.7 83.9 87.0
.85 72.2 83.5 89.5 93.1 95.3
.90 81.0 91.9 96.2 98.1 99.1
.95 90.2 97.7 99.4 99.8 100.

Of course this doesn't clarify how DCs should be assigned, but these are the probabilities we need to compare things.

 

[MyrddinE]

Consequences for Failure

The way I see it, the consequences for failure at the typical skill check is notably lower than that for failure in combat; thus, failure can be more common.

Using the chart above, and the theory that some checks in a skill encounter will be easy (aided by others, smart idea, etc) while others difficult (nobody has a relevant trained skill), I'd say that my group will likely be succeeding around 2/5 of the time on simple challenges, and 1/4 on complex challenges.

If the consequences for failure are drastic... such as death... then the challenge should be easy. It's as simple as that. Combat challenges are EASY for equal level fights, and moderate for hard boss-level fights... combat fights are NEVER difficult unless you go beyond the recommended level ranges. Skill challenges are harder by default because they are hinderances rather than life or death struggles most of the time.

You want some information about the baron? Maybe you can research history in the local archive... it's a difficult challenge to do, but if it fails you can try other challenges; you aren't going to die, but you might be tossed into a fight (an easy challenge).

 

[Inf Class]

I'm sorry if this has been pointed out already:

The footnote you mention (the +5) is for skill CHECKS, not skill CHALLENGES. The DMG notes that checks and challenges are very different. My interpretation will be that +5 is only for singular checks. I don't feel like doing the math, but this should increase the chances of success by at least 20%, shouldn't it?

 

[Spatula]

Welcome to EN World!

I'm sorry if this has been pointed out already:

The footnote you mention (the +5) is for skill CHECKS, not skill CHALLENGES. The DMG notes that checks and challenges are very different. My interpretation will be that +5 is only for singular checks. I don't feel like doing the math, but this should increase the chances of success by at least 20%, shouldn't it?

But a skill challenge is made up of skill checks. As mentioned, the web extra skill challenge for KotS uses the lvl 4-6 DCs with the +5 added in. The one challenge present in the published KotS uses DC 15, which would seem to imply not using the +5, but it also involves 4 successes before 4 failures (instead of 2), so it's not a standard skill challenge (or a beta version, at least).

Perhaps the designers are just as confused as we are.

 

[Terramotus]

Does this math match up with anyone's play experiences? I have trouble believing that playtesters worked at this game for as long as they did without ever noticing that their party fails 80% of all skill challenges. Perhaps some factor is being omitted?

We ran two different skill challenges tonight. Both were straight out of the book. We, as the players, quickly realized that we had virtually no chance of successfully completing the Complexity 5 Urban Chase out of the book. The only option we saw was to have everyone do Perception (which doesn't cause you to succeed or fail, only provide a +2 or a -2 on the next roll) over and over until it was the turn of the guy with a +10 to Athletics and the guy before him got lucky with perception.

We decided that was utterly ridiculous. The DM ended up deciding to remove the +5 for skills, which, of course, made things much easier, perhaps a bit too easy.

It was the same thing in the second challenge too. We had to remove the +5. We're currently looking for a sane solution. As written, though, they're utterly broken, especially since you can't assume that every PC will have a good skill for the situation.

 

[FireLance]

The math behind skill challenges bothered me too. Then, I looked at the higher-level DCs and noticed something interesting (numbers from pg 42 of the DMG):

For levels 1-3, a moderate check was DC 15 (DC 20 for a moderate skill check).

For levels 28-30, a moderate check was DC 29 (DC 34 for a moderate skill check)

A 30th level character would have a +15 for level, say a +6 from ability scores, a +5 for skill training, and an unknown amount from magic (I haven't digested all the powers and magic items yet), for a total of +26. A trained character would thus succeed 65% or more of the time on an individual skill check, making it more likely that he can overcome a skill challenge without assistance.

So, the skill challenge system for 4e seems to require characters to work together (using Aid Another) to have a decent chance of overcoming the skill challenges at low levels, while allowing them to function more independently at higher levels.

So, what do you think: bug or feature?

 

[Terramotus]

The math behind skill challenges bothered me too. Then, I looked at the higher-level DCs and noticed something interesting (numbers from pg 42 of the DMG):

For levels 1-3, a moderate check was DC 15 (DC 20 for a moderate skill check).

For levels 28-30, a moderate check was DC 29 (DC 34 for a moderate skill check)

A 30th level character would have a +15 for level, say a +6 from ability scores, a +5 for skill training, and an unknown amount from magic (I haven't digested all the powers and magic items yet), for a total of +26. A trained character would thus succeed 65% or more of the time on an individual skill check, making it more likely that he can overcome a skill challenge without assistance.

So, the skill challenge system for 4e seems to require characters to work together (using Aid Another) to have a decent chance of overcoming the skill challenges at low levels, while allowing them to function more independently at higher levels.

So, what do you think: bug or feature?

Bug, because none of that is mentioned at all. In fact, The wording for skill challenges very strongly implies that you CAN'T aid another, unless there's a specific skill for that task (such as Perception, in some of them). It also seems to be a bit of an exploit of the existing system to tie everyone up in an endless loop of Perception checks until the guy with the best odds comes up. Not to mention boring as hell on the higher complexity skill challenges.

If there is something missing, or some sort of misprint with the +5 for skill checks, then someone from WotC needs to address this. As written, the system just doesn't work.

 

[helium3]

We ran a 10th level skill check today as part of the mini-adventure I'm running them through. I did not include the +5 to Skill Check DC's, as I hadn't seen the foot-note the rest of you are talking about. Even then, they barely succeeded and only after a bunch of them started to aid some of the other characters. Now that it's been pointed out, Aid Another doesn't really seem like an option so I'm inclined to think there's merit to the idea that the skill challenges don't work very well.

 

[hong]

Bug, because none of that is mentioned at all. In fact, The wording for skill challenges very strongly implies that you CAN'T aid another, unless there's a specific skill for that task (such as Perception, in some of them).

?
The "Group Skill Checks" section in the Skill Challenges chapter would seem to be specifically about aiding another.