How can I use the skill system from D&D3e in AD&D2e?

Question

How can I use the skill system from 3rd edition in a 2nd edition game? Are there any problems with just adding it as-is? Are there any good houserules online?

Personal experience is much appreciated. I would only want to add skill points to replace non-weapon proficiencies, although answers about adding feats as well are better than none.

Answer 1

There's good news and bad news

The good news is that, as you've probably noticed, the non-weapon proficiency system is very ill-defined and thus easy to replace.

The bad news is that the skill system from 3.X works around a system of ranks vs. a target number (DC) that can be determined by all kinds of assumptions that 2e doesn't actually have. For example, Knowledge checks in 3.X predicate off of hit dice, which are "assumed" (somewhat erroneously, since the designers didn't bother being very consistent) to fall within certain ranges at certain Challenge Ratings, which is another new idea to 3.X.

If it's still your ambition to use the 3.X system, some considerations:

• Decide if you want to consolidate the skill list to make it smaller and less headache-inducing, or if you want to keep it as-is. I'd suggest consolidating it, as there's a lot of tiny niche skills and redundancies that frankly should just go, and those niches make the skills in question (like Forgery) difficult to counter.

• Skills in 3.X are based on ranks, which are granted by one's class. How many ranks should each class/character get? Difficult to say, but the easiest thing to do is just import the amounts from 3.X whenever possible and grant bonuses for high Intelligence (you can find the modifiers in the 3.X SRD). As a personal suggestion, I'd give everyone an extra four ranks per level, just because there's never enough skills to go around, though if you consolidate the skill list you could probably get away with just two. 3.X caps the max ranks in any one skill to 3 + your level (1/2 that for cross-class skills if you're using class skills as a concept); I'd suggest following this model.

• Decide if you want to use the 'class skills' system. You can find examples of class skills in the 3.X SRD, but note that this concept (originally spawned in 2e) has largely been abandoned by the community because it limits character concepts (flavorfully) rather than enhancing them and also needlessly punishes some classes by taking away skills they need to do their job (such as how Fighter lacks Spot or Listen entirely). If you feel the need to embrace class skills, I'd suggest the Pathfinder version (see the PFSRD).

• I don't have a comprehensive guideline for skill check DCs for you, but a great rule of thumb is this - an "even" level-appropriate challenge should require a player with just ranks and maybe a +2 ability modifier (like rolling Spot with a 14 Wisdom) to roll a 10 or higher to pass. If the player has invested in the skill somehow (maybe their class is especially perceptive, or you give them an item that increases it) or the check is easier (the monster is bad at hiding) then you should eyeball it as low as about six. If the character is bad at the skill (they're poor of sight) or the check is more difficult (the monster is good at hiding) then maybe eyeball it up to about a 15. Whether or not it's legitimate to offer impossible skill checks at a certain level is beyond the scope of the question, but you can certainly set a DC at 30 or so and expect them to come back when they're higher level.

• Some skills assume systems that 2e doesn't have, with Tumble and Concentration being prime examples. I'd cut those skills entirely and fold any applicable aspects (like absorbing fall damage) into another skill.

Answer 2

The Non-combat proficiency system isn't that bad. It just needs a couple tweaks and can easily pass as a 3rd style skill system....just add additional NCP points at creation, and maybe tweak the rate at which they're gained when leveling to whatever you feel sounds appropriate and add a few new proficiencies to cover things with no current skills, and allow retries on things that make sense to allow additional chances. Instead of a DC, you just make a bonus or penalty on the roll depending on how easy or hard the check is. Attempting a skill you aren't proficient in applies an +3 penalty on top of other modifiers, and an additional +3 penalty for attempting skills from pools you don't have normal access for (a fighter attempting an non-proficient wizard pool check would have +6 to the roll, but only +3 to a skill from the warrior or general pool, though a particularly intelligent fighter could still potentially have a chance at pulling it off. While a Bard would only get +6 attempting to use priest pool skills, since they get regular access to all pools but priest). The first point in a NCP spent removes the penalty, while each additional point gives a bonus to check results.

I'd also add new NCP that can replicate some thief skills in the rogue pool, but are less efficient, since they're taking up NCP points, and have high dex/int penalties (Thieves can simply ignore these and use their class based skills instead), and for non-bards would cost 2 NCP per point, unless a kit changed that access.