Critical Strike Chance gives a random chance to make a Critical Strike which is based on a player's Critical Strike Chance stat.
Critical Strike Chance stats can be boosted from the base of 5% with a further 0.02% added per point of either Intelligence or Dexterity. The stat can be further boosted by stats on gloves and rings as well as skills and passives.
Note that damage is split into direct damage and damage over time. Critical Strikes are dealt with direct damage and not damage over time.