Ability checks are powerful tools the DM use in a wide array of situations. They allow you to run and control the flow of the game, and to arbitrate and resolve conflicts.
They are also simple: roll a d20, add the relevant ability modifier, and your proficiency modifier. For instance, if you are trying to snatch the purse of a merchant, the DM might call for a Dexterity (Sleight of Hands) check. Dexterity is the relevant ability, and Sleight of Hands is the relevant skill. You might even be a Rogue who has Expertise in Sleight of Hands, highly increasing your odds of success.
This particular check uses a skill, one of the eighteen listed in the game. But the way skills are written in the Player’s Handbook, they are innately tied to an Ability score. Often, the ability score is omitted. E.g. when the DM calls for a Perception check, we make a Wisdom (Perception) check.
The variant rule
Now there is a neat little variant rule in the Player’s Handbook that says the DM can ask for a skill check with another ability score if appropriate. For instance, a rough character could intimidate an enemy by flexing their muscles, or lifting and hurling a nearby boulder. This would be an excellent occasion for a Strength (Intimidation) check. I encourage you to use this variant rule as much as possible as it opens up possibilities. It rewards creative-thinking, and enables less reliance on rigid abilities score.
And to inspire you, here are a few examples of applying this variant rule:
- Passing of as a historian at the queen’s banquet could be Intelligence (Deception), as you use sophistry to hide your ignorance.
- If you try to hide your spellcasting: Spellcasting Ability (Deception) as you try to appear inconspicuous, or Spellcasting Ability (Sleight of Hand) as you try to keep your focus and somatic components out of sight.
- Convincing a barbarian tribe to join you by lifting a heavy boulder in a dramatic manner: Strength (Persuasion).
- A delicate surgical operation that requires a steady hand would be an excellent occasion to do a Dexterity (Medicine) check.
- For your next infiltration mission, you observe the schedule of the patrols and relieving. By timing your movement and relying on your memory, you can avoid patrols: Intelligence (Stealth) check.
- Blending into a crowd as a local: Charisma (Stealth) check (vicious_snek from Reddit).
- Wall Jump/Climbing jumping from ropes to ropes: Dexterity (Athletics) or Strength (Acrobatics).
- Hurting yourself to intimidate an enemy (for instance, knocking a wall with your solid shining bald head): Constitution (Intimidation).
- Playing with a butterfly knife or juggling and throwing shurikens to intimidate small-time thugs : Dexterity (Intimidation).
- Juggling: an obvious Dexterity (Performance).
- Funding speech for your next cult: Charisma (Religion).
- Rodeo: Constitution (Animal Handling), and more generally Constitution (X) for any task involving the skill X and depending on stamina more than anything else.
- You need to test wildlife plants in this new unfamiliar environment where you just have teleported? Constitution (Nature) or Constitution (Medicine).
- Predicting an enemy’s next move: Intelligence (Insight). While Wisdom (Insight) would work — in fact it is one of its main use —, if the prediction is made based solely on logic, Intelligence makes perfect sense here.
- Solving a puzzle in limited time which requires nimble fingers (like a Rubik’s cube): Dexterity (Investigation).
- Tie a Knot: Intelligence (Sleight of Hand) from Xanathar’s Guide to Everything‘s rules on tying knots. Intelligence (Survival) might also make sense.
A more in-depth look.
You can notice those examples emphasize two different aspects tied to two different ability scores. For instance, solving a puzzle in limited time involves a measure of intelligence or memorization, but also quickness. The variant rules shine here as it allows us to reward those two aspects, instead of having to choose one and ignoring the other.
This idea is also touched upon in Xanathar’s Guide to Everything in another form. If a PC is proficient in both a skill and tools relevant to the situation, the DM could give them advantage on the check. E.g. someone proficient with the Alchemist kit and the Arcana Skill is doubly qualified to investigate a wizard’s laboratory. The idea can be extended to all checks without any difficulty.
And last, raw pure checks are also interesting in their own regards, when there does not seem to be an ability check to tie.
At this point, or right from the start, you might have asked yourself why bother, won’t it be the default PHB ability score most of the time? Not to mention the lack of proficiency might make the ability check a simple raw check. It might be, but the few cases where you go into a different direction, the players that enjoy solving conflicts through creative thinking are going to enjoy it, even if your choice of ability is at their detriment. In fact, if a player makes a convincing argument to use another ability score than the default one, you should allow it.
Next time, we shall take a look at passive scores and how to use those, beyond the simple textbook use of passive perception.
Strength checks, not Athletics checks!
Side note, the Strength section of Using Each Ability (PH125), is of particular interest and I recommend its reading. Here you learn that Athletics should be used for climbing and pulling, lifting or carrying any objects would be excellent Strength checks (just a pure raw Strength check, not Athletics). I would recommend following those guidelines as a way to promote Strength differentiation in the party, and punish Strength dumping. The way a party deal with a shared common weakness is as interesting as the way a particular individual can shine through their strengths.