In the Unite States, comparative negligence is a partial defense that reduces the amount of damages that a plaintiff can recover in a negligence-based claim based upon the degree to which the plaintiff's own negligence contributed to cause the damages. When this defense is asserted, the fact-finder, usually a jury, must decide the degree to which the plaintiff's negligence versus the combined negligence of all sued defendants contributed to cause the plaintiff's damages. It is a modification of the doctrine of contributory negligence, which disallows any recovery by a plaintiff whose negligence contributed, even minimally, to causing the damages.