California civil code states that a person is responsible for injury caused to another by want of ordinary care or skill in the management of their own property or person. That means that if a defendant, using reasonable care, skill, or judgment, should have expected that the possibility of causing harm to someone, the defendant will be found to have been negligent. Most states have similar definitions of negligence. However, when both parties are partially at fault, the states differ on how they treat that joint responsibility.