Skill Checks


The rules below modify and enhance the skill check system presented in the 5e rules. The intent is to fix situations like the following:

Five people with average intelligence and no meaningful life experience of any kind (INT 10, no related proficiencies) examine a moldy book found in a library with a strange coat of arms on the cover. An Intelligence (History) check would reveal this to be the symbol of a long-dead noble household the group is hoping to learn more about (Obscure knowledge, Hard check, DC 20). Do the characters know the connection? According to the rules, everyone should make the Intelligence (History) check. Since a natural 20 is required to succeed, each person has a 1 in 20 chance of knowing the connection. The question is: how likely is it that the party as a whole succeeds on this check?

It turns out that at least one person in the group would make the check 22.6% of the time even though each of them have only a 5% chance individually of doing so. This is because individual skill tests performed as a group with a single desirable outcome creates a binomial probability where the sum is much greater than its parts. If we increase the number of people participating to 10, the probability of at least one person succeeding on the check raises to 40.1%. Certainly, having another person or two around may help a bit, but really, adding more people of the same intelligence and (lack of) training should have no measurable outcome on the likelihood of knowing an obscure historical fact. In actuality, adding more untrained people to a task makes it less likely that the group will settle on an accurate finding! This issue arises again and again in the game; a secret door doesn’t remain secret for long, parties don’t get lost when wandering the wilderness, tracks are easy to find and follow even in difficult conditions and even obscure hieroglyphics would be deciphered just by calling upon enough peasants to interpret the sigils. In short, completely average people (let alone heroes) are always going to be able to perform so much better as a group that they succeed on many tasks that individually they otherwise would have very little chance of completing simply because more people are present. This not only leads to nonsensical outcomes, but metagame thinking may lead players to create a party of heroes with lower ability scores in certain areas, knowing that (for example) at least one person’s rolls are likely to be high enough out of sheer luck that the party will overcome any challenge that would otherwise impact their collective weak spot.While there is nothing inherently wrong with following the rules as written to optimize outcomes, when the rules lead to nonsensical outcomes or drive behavior that runs counter to the game’s objectives (obscure knowledge is obscure, for example, independent of the number of uneducated guessers present), then a rule change is required.

Skill Checks - Individual vs Group

When the DM determines that a skill check is necessary or the players determine they wish to use a skill, the DM must examine the the situation to determine if the skill check should be done on an individual basis or as a group. Situations arising in game are so diverse that a hard and fast rule here is impossible. The goal is for the DM to determine if the party as a whole, instead of an individual character is collectively attempting to accomplish the goal. Some examples follow:

Use individual checks when each person is acting wholly on their own AND the situation is time critical or has a critical outcome that could affect only that character. Some examples include:

  • Characters swept away in a flood make individual swim checks
  • Characters trying to climb trees to avoid wolves make individual climb checks
  • Characters are individually challenged to a riddle game by a sphinx where cooperation is impossible
  • A character attempts to climb a statue to pry the gems from its eyes or attempts to climb a cliff to rig ropes to allow less-skilled climbers to ascend.

Use group checks when the outcome affects the group as a whole OR the situation is not time critical or has no critical outcome for an individual character. Some examples include:

  • The party believes they may be lost and want to try to get their bearings
  • The party has to climb a cliff or cross a body of water and they are not under pressure to do so
  • The party is trying to search for clues, tracks or secret doors
  • The party is attempting to use Intelligence-based knowledge skills to glean information or clues
  • The party is attempting to negotiate with or threaten an NPC
  • Any other situation where the number of participants should not measurably affect the outcome in the DM’s opinion.

Individual skill checks are handled per the rules as written. For group checks, use the following rules:

  • The DM first determines the qualified participants in the group check. Typically, this is done by deciding on the minimum skill check bonus required for a participant. Participants that lack this minimum bonus cannot participate in the group skill check. The DM is free to make allowances for character background or other circumstances that may provide a character the ability to contribute instead of or in addition to setting a minimum bonus. The DM should also account for characters with items or tools that allow them to participate even if their base modifiers are otherwise too low.
  • The party designates a leader that will actually perform the check from among the qualified participants. Typically, this will be the character with the highest proficiency bonus in the check being made.
  • All qualified participants make the appropriate skill check. The leader’s result is the base result, but this can be raised by +2 for each other participant whose check meets the DC. In addition, if any participant beats the DC by 5 or more, they add an additional +2 to the leader’s check for each increment of 5 they exceed the DC.
  • The results are determined normally, and the party as a whole receives the outcome.

For Charisma, Intelligence or Wisdom-based checks, a failure is just that - the group goal was not accomplished. For Strength, Dexterity or Constitution-based checks, the party either fails with our without some cost or succeeds at some cost. Thus a failed group climbing roll means that the cliff was a too difficult to climb, or that it was a very difficult climb and left each party member with a level of exhaustion or that the climb occurred but one or more of the party (chosen at random or by some other method) suffered some kind of setback, like receiving a level of exhaustion or even a fall.