Mechanics

Terms

The entire process is called a test. An individual roll is called a check and results in either a success or a failure.

Setup

  1. The starting DC is 8 + (Player Level / 3, round down). Alternately you can use 8 + (CR / 3, round down) if that feels appropriate the the situation. For example, a complex trap with a specific would use the DC of the trap.
    1. If the difficulty should be in reaction to a variable condition you can have the PCs make 3 checks with 3 different skills. The DC is the DC of a moderate check for their level. 0 successes = difficult, 1-2 success = moderate, and 3 successes = difficult. {1
  2. Decide if this is a trivial, moderate, or difficult challenge.
  3. Adjust the DC based on the difficulty of the challenge.
    1. For a trivial challenge do not change the DC. the PCs will very rarely fail a trivial challenge. An expert essentially cannot fail a check. This will require 3 successful checks.
    2. If the the puzzle is moderately hard, the enemy has a slight advantage, or creature is skeptical of the PCs, +2 to the base DC. The PCs are somewhat likely to pass this test, failing about 25% of the time. An expert will only rarely fail at tier 1 and tier 2. This will require 4 successful checks.
    3. If this enemy is opposed, the PCs are in over their heads, or the PCs start off behind, then this is a difficult challenge. Add 4 to the base DC. The PCs will pass this test about half the time. An expert is likely to pass at tier 1 and two, and almost never fails at tier 3 and 4. This will require 5 checks.
Trivial Moderate Difficult
1- 5 8 10 12
6-10 10 14 16
11-15 12 16 18
16-20 14 18 20
Number of Successes 3 4 5
Approximate Success range 90-100% 60-90% 30-65%

Flowchart