Plaintiff’s Burden of Proof in Personal Injury Cases

Clayton T. Hasbrook

Written by Clayton T. Hasbrook. Last modified on February 20, 2024

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In Oklahoma personal injury law, the injured party who brings a lawsuit is known as the plaintiff. The plaintiff is responsible for proving their claims and showing that their account of the incident is more plausible than the defendant’s. This involves demonstrating that the defendant’s negligence or failure to fulfill a duty caused the injury.

The standard of proof in these civil cases is called “greater weight of the evidence.” This means that the Plaintiff must show that their version of events is more likely to be true than not, exceeding a 50% likelihood.

Defining the Burden of Proof

The burden of proof refers to the Plaintiff’s obligation to prove that the defendant is liable for the harm suffered. As the person bringing the lawsuit, you must provide evidence that the defendant’s actions or inactions directly led to your injuries.

In civil cases involving personal injury, the burden of proof is “preponderance of the evidence” or the “greater weight of the evidence.” This means you must show there is more significant than a 50% likelihood that your version of events is accurate and that the defendant breached a duty, resulting in your damages. This is a lower threshold than the “beyond reasonable doubt” standard in criminal cases.

Sample Jury Instruction on Burden of Proof

In a civil lawsuit, such as this one, the law provides which party is to prove certain things to you. This is called “Burden of Proof.”

When I say that a party has the burden of proof on any proposition by the greater weight of the evidence, or use the expression “if you find,” or “if you decide”, I mean you must be persuaded, considering all the evidence in the case, that the proposition on which such party has the burden of proof is more probably true than not true. The greater weight of the evidence does not mean the greater number of witnesses testifying to a fact, but means what seems to you more convincing and more probably true.

A party who seeks to recover on a claim [or counterclaim], or a party who raises an affirmative defense has the burden to prove all the elements of the claim or defense. In deciding whether a party has met the burden of proof, you are to take into account all the evidence, whether offered by that party or any other party.

Proving Negligence

To establish negligence under Oklahoma law, you need to show:

  • The defendant owed you a duty of care
  • The defendant breached this duty of care
  • Their breach of duty directly caused your injury
  • You suffered measurable harm

Thoroughly documenting all injuries and losses strengthens your ability to secure compensation proportional to the damages. Records like medical bills, lost income data, and pain and suffering diaries are beneficial evidence.

Establishing Duty and Breach

Proving negligence requires showing:

  1. The defendant had a legal duty to act with reasonable care towards you
  2. The defendant breached this duty through inappropriate actions or failure to act
  3. A direct link exists between the breach of duty and the injury sustained

Your evidence must satisfy the “preponderance of evidence” standard, meaning your argument should convince the court there is a greater than 50% chance your claim is valid.

Causation Evidence

You must provide persuasive evidence demonstrating that the defendant’s negligence likely caused your injuries, with over a 50% probability. This evidence should connect the breach of duty to the resulting harm, painting a vivid sequence of events for the jury. Establishing this causal link is essential for receiving compensation for damages.

Damages Documentation

Precisely recording damages is vital for supporting personal injury negligence claims. Useful documentation includes:

  • Medical bills tallying financial losses
  • Lost income data demonstrating the economic impact
  • Diary of Pain and suffering establishing non-economic harm

Thorough records help ensure all aspects of your losses receive recognition and fair compensation. It’s also wise to act promptly before the statutory limitations period affects your ability to file a lawsuit.

Slip and Fall Premises Liability Law Example

In a slip and fall case vs. Walmart, for example, the Plaintiff has the burden of showing:

  1. The defendant had actual or constructive notice of the dangerous condition that caused the fall and failed to warn about or remedy it. This requires showing that the condition existed for long enough that the defendant knew or should have known about it to take reasonable steps to address it. OR
  2. The fall was proximately caused by a dangerous method of operation or display of goods, such that injury was reasonably foreseeable. This removes the notice requirement and focuses on whether the defendant’s choices created conditions likely to cause harm that the defendant should have anticipated. The key factors are whether the condition was known or apparent to the Plaintiff, whether the defendant created or enhanced the hazard beyond typical weather hazards like snow/ice, and whether the specific accident was foreseeable due to prior incidents or the nature of the situation. The core issues are the reasonableness of the defendant’s actions and knowledge compared to the Plaintiff’s. The Plaintiff bears the burden of proof on these issues.

Actual Premises Liability Case Examples

  1. Walmart had a leaky water fountain. Since the fountain had been an issue for several weeks, Walmart had reasonable notice to fix the dangerous condition. Thus, Walmart was liable for the damages caused by their customer’s slip and fall.
  2. A Walmart employee cleaned a checkout lane but didn’t finish. The employee left large (hidden) puddles of clear cleaning solution in the walkway. Since Walmart created the dangerous condition and did nothing to warn its customers, Walmart was responsible for the damages caused when a customer walked through the area.

Examples of When a Store is Likely Not Liable for  a Customer’s Slip and Fall

  1. A customer spills a beverage, and within a few seconds, another customer walks through the spill. Since Walmart did not have reasonable notice, the store could not have prevented the injury.
  2. A customer sees a wet floor sign beside a large puddle of spilled orange Gatorade. Since the customer saw the danger, Walmart wouldn’t generally be liable.

Evidence Helpful for Burden of Proof

To prove liability in a personal injury case, compelling evidence is required, typically including:

  • Photographs: Visually documenting injuries, property damage, unsafe conditions
  • Witness statements: Accounts from eyewitnesses supporting your version of events
  • Video evidence: Potential footage from surveillance cameras capturing the incident
  • Medical records: Documents validating injuries sustained
  • Expert assessments: Analyses from accident reconstructionists, medical experts, etc., lending credibility

Does the Defendant Have to Prove Anything?

No, the Plaintiff shoulders the responsibility of proving their case. The defendant simply needs to raise doubts concerning the Plaintiff’s evidence validity to weaken their case without needing to disprove it conclusively. However, supporting evidence becomes the defendant’s responsibility if the defendant claims affirmative defenses like contributory negligence. They aim to make the jury question the Plaintiff’s version, not outright disprove it.


This page has been written, edited, and reviewed by a team of legal writers following our comprehensive editorial guidelines. This page was approved by Founding Partner, Clayton T. Hasbrook who has years of legal experience as a personal injury lawyer. Our last modified date shows when this page was last reviewed.