D&D 5E Changing Expertise and Ability Check Resolution - House Rule

Problems:
1. Perceived need to proliferate Expertise (doubled proficiency bonus) to sub-classes beyond Bard and Rogue and the expectation that Expertise is required to actually excel at a skill.
2. Skill check number porn. Especially stealth and perception; and other opposed checks.
3. Lack of love for balanced stats. Stats tend to be high (16+) or low (10 or less).
4. Everybody rolls wonkiness.

Ability check modifying house rule suggestions:
1. Expertise replaces the stat part of the Stat bonus plus Proficiency of Ability check resolution. So it makes up for a weak stat or at the highest tier allows a character to exceed the stat limitation (default of +5). It allows a character to be good at something they might not have a natural aptitude for (the high stat). So +4 to +12 in a specific skill. Expertise at level 1 or 2 is a +4 bonus. A high stat and proficiency could be higher.
2. A good stat or proficiency lowers the DC of a static check by 5 (takes inspiration from the Lore check in the playtest and +3 bonus of 3.x, +5 bonus of 4e). For point buy or default array I'll peg 'good' at 14+ (+2 bonus). For high rolled stats I might push it up to 15 or 16.
3. Opposed checks are not effected. (Not using the effective +5 bonus. This results in an advantage rather than an overwhelming advantage).
4. Pass without Trace. The +10 bonus to stealth replaces the normal bonus. Stacking the +10 with the normal bonus results in a higher bonus than I prefer. I believe replacing the complete bonus gives the world better reference for the skill level of a high stealth character - they effectively can approximate Pass without trace at will.

Not really a house rule but I use the Middle path in the Role of the Dice DMG section - my criteria for Auto-pass or auto-fail is based on needing a 18+ for success or a 3 or lower for failure. Outside a 20-80% uncertainty window I'd prefer to not have player's roll. This is a result worse than a 1 in 6 chance so common in 1e.

Goals:
1. Let martial strength types excel at grappling without needing to dip Rogue/Bard.
2. Bump up the mental stats with their large number of associated skills. Bring up the success rates of the Lore abilities and other non-opposed checks.
3. Make the choice of which abilities to apply Expertise to more interesting (IMO). Making your best skill better is not a very interesting choice personally. (Static checks like Picking locks, finding traps, tool proficiency, etc. get 'free' Expertise+ early on).
4. Removing the stacking on PwoT. "I get a 42 on my stealth check" distorts the skill system and the "DM decides" hiding resolution.
5. A natural mechanical disincentive to 'me too'ism on skill checks a character has no natural ability in.

My preference would be the think of the skill bonuses more on a scale of 1-10 rather than 2-17. I'd also cap stats at 18 but that is more related to making combat more challenging at the higher tiers and encouraging more feat taking.

Thoughts, issues, or unforeseen complications?

To address a similar list of problems, we went far simpler for our home games; anyone can expertise. If you put proficiency in a skill twice, it becomes expertise. In example, Fighter can simply pick Athletics twice if they care about their shoving (like the shield master feat). Bard and Rogue then simply get yet more skill 'points' at their expertise levels. That's the long and short of it; fixed a whole lot of dipping needs, let characters specialize at the loss of broad depth of knowledge, and the number sizes were never an issue for us.

Item 2 is wonky for a couple reasons

A) In effect, it's adding a +5 bonus for a stat going from 13 to 14 (or whetever you set the threshold for the change)
B) It means you as DM have to either know all the players stats or ask them what their stat is every time you set a DC.

That B would drive me bonkers as a DM. As for A, It's just gonna push minmaxes to reach the threshold and stop, I'd think.

I have an alternate suggestion for you that could work. It minimizes Expertise while still keeping it interesting, and gives higher stats greater oomph in opposed rolls. Consider this:

Leave everything in the rules the way it is, but this: Double the ability score modifier for ability checks.

For added complexity, do that for checks with Static DCs, but triple the modifier for opposed checks.

Simplier rules.
A skill check cannot have a total bonus more than +12.
A trained skill use a minimum stat bonus of +2.

Satyrn said:

Item 2 is wonky for a couple reasons

A) In effect, it's adding a +5 bonus for a stat going from 13 to 14 (or whatever you set the threshold for the change)

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Yes. But why would you stop at 13 intentionally? To pump up something else you wanted more or meet a multi-classing req?

Satyrn said:

B) It means you as DM have to either know all the players stats or ask them what their stat is every time you set a DC.

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I think in play it'll be more likely that the player trying first will have the stat or proficiency to get the bonus so I just give them the DC with the -5 included. When a 'me too' character asked for the check I'd ask if they are Skilled (having +2 or better stat, or proficiency) otherwise I'll add 5 to the stated DC. But I can pick up pretty quick where the player's put their abilities.

Satyrn said:

As for A, It's just gonna push minmaxers to reach the threshold and stop, I'd think.

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Exactly! Making minmaxers create more balanced characters is a nice side effect and related to Problem 3.

Satyrn said:

Leave everything in the rules the way it is, but this: Double the ability score modifier for ability checks.

For added complexity, do that for checks with Static DCs, but triple the modifier for opposed checks.

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If the current range for checks is -1 to +17 static or opposed and I think that difference is too big, why would I want -2 to +22 or even worse -3 to +27 on an opposed check?

From another way of looking at the math I'm shifting the modifiers to -6 to +12 for static checks but they narrow to -1 to +12 for opposed checks. Practically I'm actually applying a -5 penalty to unskilled checks. If a player didn't care enough to get a stat to +2 bonus, or gain proficiency then I don't feel bad if the character has a statistically significant reduced probability for success on a check. Because I want the invested characters to have a much higher chance of success starting from level 1.

Krachek said:

Simplier rules.
A skill check cannot have a total bonus more than +12.
A trained skill use a minimum stat bonus of +2.

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That was pretty close to where is started but I didn't want to screw the Expertise users too much since they'd still Expertise their best skills to cap quickly but then they'd be hosed moving beyond that.

Let's take any Dex skill as a Rogue with point buy/array and Expertise.
Dex 16, Expertise at 1st: +7 (85% Easy DC 10, 65% success rate against Average, and 40% against Difficult DC 20, 15% at Very Difficult)
Dex 18, Expertise at 5th: +10 (80% at DC15, 55% at Difficult, 30% at Very Difficult)
Dex 20, Expertise at 9th: +13 - capped at +12 (90% average, 65% Difficult, 40% at Very Difficult, 15% at Nearly Impossible)

Starting at 8th you start getting weird. Proficiency beyond 9th is wasted. Do you let them move Expertise to another skill?
But then they are back down to +9 after being +10 starting at 5th.

jodyjohnson said:

That was pretty close to where is started but I didn't want to screw the Expertise users too much since they'd still Expertise their best skills to cap quickly but then they'd be hosed moving beyond that.

Let's take any Dex skill as a Rogue with point buy/array and Expertise.
Dex 16, Expertise at 1st: +7 (85% Easy DC 10, 65% success rate against Average, and 40% against Difficult DC 20, 15% at Very Difficult)
Dex 18, Expertise at 5th: +10 (80% at DC15, 55% at Difficult, 30% at Very Difficult)
Dex 20, Expertise at 9th: +13 - capped at +12 (90% average, 65% Difficult, 40% at Very Difficult, 15% at Nearly Impossible)

Starting at 8th you start getting weird. Proficiency beyond 9th is wasted. Do you let them move Expertise to another skill?
But then they are back down to +9 after being +10 starting at 5th.

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Maybe try expertise = advantage. It's a great bonus, but limit the maximum you get get. Advantage efficiency is maximized when you get a 50% success chance. But when you have a fair or a poor chance, a straight bonus is more interesting.

Otherwise it is the whole system you have to redo.
My own interrogation is : Why a Fighter with 14 dex and 14 str is not as effective than a fighter with a 16-10 to 10-16 in the same stat?
It would be fun to have a multi-stat bonus system, but it will be much arder to apply.

jodyjohnson said:

Yes. But why would you stop at 13 intentionally? To pump up something else you wanted more or meet a multi-classing req?

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I wasn't thinking about players adjusting stats. It just the scenario where I have a 13 in one stat and 14 in another. The 14, instead of being +1 over 13 is suddenly +6 over it.

Meanwhile, a 16 is only +1 over 14.

It just feels wonky to me that there's one point where the ability score check modifier has such a giant leap.

[MENTION=5590]jodyjohnson[/MENTION]

I share the same concerns. I strongly prefer skills use the same tight tried-and-true mathematics that combat uses, including bounded accuracy.

With regard to Rogue expertise or so on, I would rather just let the Rogue have auto-wins, than convolute the math of the gaming system.

Let us know how your play testing goes as you implement some of your proposals. If it works well, I plan to adopt them for myself.

Comparing to combat math.

Expertise can be an additional +2 to the Proficiency Bonus. (Compare the +2 attack from the Archery fighting style.)

But mainly, Expertise should mean getting more utility out of a skill. In other words, Expertise = noncombat ‘skill’ feats.

Expertise in Athletics can grant auto-win to climbing walls for one feat, and a spell-like ability to Jump for an other feat. Expertise in Arcana might allow the ability to use an action (at-will or per short rest or instead a 10 minute ritual) to detect the presence of magic nearby (but not necessarily its direction or location). Or so. Just brainstorming topics that this design space might include.

Because regular feats are so important for combat, the noncombat feats rarely see the light of day.

But ‘expertise’ can become the new design space for noncombat feats.