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.

In Ohio, the state follows a modified comparative negligence system. Under this system, a plaintiff's recovery is reduced by their percentage of fault. However, if a plaintiff is found to be 50% or more at fault for the cause of the accident, they are barred from recovering any damages. This approach is designed to allocate damages in a more equitable manner, allowing plaintiffs to recover compensation even if they are partially at fault, as long as their fault does not reach or exceed the 50% threshold. Ohio's adoption of the modified comparative negligence rule reflects a shift from the traditional contributory negligence doctrine, which would completely bar recovery if the plaintiff had any degree of fault. It's important to note that negligence laws can be complex and subject to change, so consulting with an attorney for the most current advice is advisable.