Contributory negligence is a common law tort rule (created by judges in court opinions, judicial decisions, or case law) that bars or prevents a plaintiff from recovering on a claim for negligence if the plaintiff contributed to the cause of the accident (was contributorily negligent) in any way. This rule may be referred to as pure comparative negligence.

Some states still apply the contributory negligence rule. But because of the harsh outcome of the contributory negligence rule, many state legislatures have enacted statutes that provide for comparative negligence or fault and reduce the plaintiff’s recovery by the amount of the plaintiff’s negligence or fault. This rule may be referred to as pure comparative fault.

Other states have enacted a modified comparative fault statute or law that reduces a plaintiff’s recovery by the plaintiff’s percentage of fault, but bars a plaintiff from any recovery if the plaintiff is 50% or more at fault for the cause of the accident.

And in South Dakota, the comparative fault system uses a slight/gross negligence system and only analyzes the comparative fault if the plaintiff’s negligence is slight and the defendant’s negligence is gross. Under this slight/gross negligence system, if the plaintiff’s negligence is more than slight and the defendant’s negligence is less than gross, the plaintiff is barred or prohibited from any recovery.

These contributory negligence and comparative fault laws vary from state to state and may change or evolve at any time—whether they are located in court opinions or in statutes.

Hawaii follows a pure comparative negligence system. Under this system, a plaintiff can recover damages even if they are found to be 99% at fault for the accident. However, the recovery amount will be reduced by the plaintiff's percentage of fault. This means that if a plaintiff is awarded $100,000 in damages but is found to be 30% at fault, the plaintiff would only receive $70,000. Hawaii's approach allows for a more equitable distribution of damages based on the degree of fault of each party involved in the incident. This system is codified in Hawaii Revised Statutes § 663-31, which states that the contributory negligence of the party injured or killed does not bar recovery if such negligence was not greater than the negligence or gross negligence of the person or persons against whom recovery is sought. It is important to note that while the pure comparative negligence rule is more forgiving than the contributory negligence rule, plaintiffs still bear the financial consequences of their own negligence in any award they receive.