With a keen eye and a calculating mind, an investigator can assess the mettle of his opponent to take advantage of gaps in talent and training. At 4th level, an investigator can use a move action to study a single enemy that he can see. Upon doing so, he adds 1/2 his investigator level as an insight bonus on melee attack rolls and as a bonus on damage rolls against the creature. This effect lasts for a number of rounds equal to his Intelligence modifier (minimum 1) or until he deals damage with a studied strike, whichever comes first. The bonus on damage rolls is precision damage, and is not multiplied on a critical hit.
An investigator can have only one target of studied combat at a time, and once a creature has become the target of an investigator's studied combat, he cannot become the target of the same investigator's studied combat again for 24 hours unless the investigator expends one use of inspiration when taking the move action to use this ability.