I'm putting together some skill challenges for D&D 4e, and I've come across some inconsistencies that I can't quite reconcile.
Let's take as an example: a single check in the context of a moderate level 4 skill challenge.
The DM Guide (p73) refers me to the table Difficulty Class and Damage by Level (p42). The entry for L4/moderate is 17. But there's a note underneath: For skill checks: Increase DCs by 5. I can't tell if this applies to skill checks in isolation during combat (which is the context of the rest of the page) or to all skill checks, ever. (If the latter, this begs the question: why not increase them all by five in the table and simplify the notes to For attacks…: Decrease by 2? Anyway…)
However, I also found this updated skill DCs table, which claims:
If you compare the new values to the DCs from the Dungeon Master’s Guide and DMG 2, you’ll notice that the DCs are higher across the board.
But the entry for L4/moderate is 14 — that's not higher than 17!
Where can I find the current, canonical, properly balanced DC numbers to use for skill challenges?
Best Answer
The Table in the Rules Compendium, in DDI and in the table on the article you linked to are the official 4e DCs for skill checks and challenges.
Yes some of the numbers went down, some of them went up. However, overall they are now normalized with more sense and math behind them.
The confusion in your second paragraph is that there is differentiation between an ability check and a skill check. This is (and should be) irrelevant most of the time. The original DC table assumed that you would make ability checks often, however, in practice this was not the case and the table had to be revised to account for skill training being accessed regularly. The instructions to increase the DC by 5 for the DMG table are to provide an advantage to having training in a skill.
In general, the revised DC table, while the value are higher, made skill checks easier because you no longer regularly add 5, and since the increase was rarely 5 (and as you point out, sometimes a decrease), skill checks with the revised DCs are actually easier. That's by design.