Checks are based on a relevant character ability, skill, or other characteristic. Most checks are either ability checks or skill checks, though special types such as turning checks, caster level checks, dispel checks, and initiative checks also exist. The specific name of the check usually corresponds to the skill or ability used.
To make a check, roll 1d20 and add any relevant modifiers. (Higher results are always better.) If this check result equals or exceeds the difficulty class number assigned by the spell, item or effect (or the opponent's check, if the action is opposed), the check succeeds.