I got that from here
Perception is a measure of the accuracy and observation skills of a character, determining its chances to score critical hits and the damage they do, its accuracy rating, its ability to instinctively identify items, to spot hidden creatures, traps and treasures and to find valuable resources while gathering.
Reaching a Perception score of 20 gives the character a significant boost to its accuracy rating.
Although Dexterity also refers to accuracy
Dexterity is a measure of the speed, nimbleness, stealth and sleight of hands of your character, determining its accuracy and evasion ratings, the cooldowns of combat-related and mobility-based abilities, the chance to inflict critical hits
Next alpha might give us the opportunity to test this.