CACI 3930: Mitigation of Damages in Personal Injury

California Civil Jury Instruction 3930 is the rule jurors use to decide whether a personal injury plaintiff’s damages should be reduced because the plaintiff failed to take reasonable steps to limit the harm after being hurt. It tells the jury that the defendant must prove any failure to mitigate, that the plaintiff is measured against what a reasonable person would have done, and that reasonable expenses the plaintiff did spend trying to recover are added into the award.¹

What the Instruction Requires

CACI 3930 has two halves, and both matter. The first tells jurors that if the defendant caused the injury, the plaintiff still cannot recover for damages the defendant proves the plaintiff could have avoided with reasonable efforts or expenditures under the circumstances, including whether the plaintiff could act without undue risk or hardship.¹

The second half is easy to miss. If the plaintiff did take reasonable steps to reduce their harm, the jury’s award should include the reasonable amounts the plaintiff spent doing so. Physical therapy, follow-up visits, assistive devices, and similar out-of-pocket costs a plaintiff paid to keep the injury from getting worse are recoverable as part of the verdict.¹

Who Has to Prove a Failure to Mitigate

The defendant does. Mitigation is an affirmative defense, and the plaintiff never carries the burden of proving they behaved reasonably after the injury. The defendant raises the issue, presents the evidence, and absorbs the consequence if that evidence is thin.¹

California appellate courts have said this plainly. In Jackson v. Yarbray, the court confirmed that while the plaintiff must prove the extent of injury actually caused by the defendant, the burden of proving that the plaintiff failed to act reasonably in limiting consequential damages rests on the defendant. Without that showing, the jury makes no deduction.¹

In practice, meeting the burden usually takes medical expert testimony tying specific missed treatment to a specific worsening of the condition, or vocational evidence tying a delayed return to work to specific lost income. A general argument that the plaintiff “should have done more” will not move the number.

What Counts as Reasonable Effort

The standard is objective. The jury asks what a reasonably careful person in the plaintiff’s position would have done, not what this particular plaintiff felt like doing.¹

Christiansen v. Hollings states the rule as “reasonable diligence” in caring for one’s injuries. What that looks like depends on the full circumstances, and no fixed rule requires the injured person to seek any particular kind of medical care.¹

Jurors typically look at what doctors recommended, whether the plaintiff followed through, and how the plaintiff’s daily conduct lines up with the injury they describe. Consistent attendance at appointments and honest efforts to follow a treatment plan usually satisfy the standard, even without perfect compliance. Conduct that flatly contradicts the claimed injury is where problems start.

When a Plaintiff Is Excused

The instruction itself carves out “undue risk or hardship,” and case law fills in what that means.¹

A plaintiff does not have to undergo a procedure that carries a real chance of making things worse. Surgery with meaningful risk of paralysis, infection, or other serious complications falls inside the exception, as does experimental treatment with uncertain results. Severe ongoing pain from a course of treatment is also a recognized limit. The court in Valle de Oro Bank v. Gamboa said the mitigation rule has no application where it would force the plaintiff to sacrifice important rights or endure impractical burdens.¹

Financial inability can also excuse mitigation. The instruction directs jurors to weigh whether the plaintiff could act without undue hardship, and California law recognizes that a plaintiff who genuinely cannot afford recommended treatment is not required to spend money they don’t have. In Valencia v. Shell Oil Co., though, the California Supreme Court noted that a plaintiff who made no effort to raise the necessary funds and offered no evidence of inability to pay could not lean on the financial hardship excuse. Some showing of actual inability is expected.¹

The through-line is that CACI 3930 asks for reasonable behavior, not heroism. A defendant cannot point to a dangerous surgery the plaintiff declined and pin the resulting disability on the plaintiff.

How the Reduction Is Calculated

When the defendant proves a failure to mitigate, the jury runs a two-step calculation. It first figures the total damages the defendant’s conduct caused. It then identifies the specific portion the plaintiff could have avoided, and subtracts that amount.¹

Take a $150,000 back injury award where the defendant proves that $30,000 of the harm came from the plaintiff skipping a prescribed physical therapy program that would have kept the condition from worsening. The jury subtracts $30,000, and the plaintiff takes home $120,000. The defendant remains responsible for everything the plaintiff could not have prevented.

This is not a percentage reduction. If the defendant’s evidence only ties $5,000 of a $200,000 award to the plaintiff’s inaction, the reduction is $5,000, regardless of how unreasonable the plaintiff’s behavior looks in general terms. Mitigation removes specific avoidable dollars, not a share of the whole.

Mitigation Is Not Comparative Fault

These two ideas get confused often, and the distinction changes the math. Comparative fault addresses the plaintiff’s conduct before or during the event that caused the injury. Mitigation addresses the plaintiff’s conduct after the injury has already occurred.²

The California Supreme Court drew that line in LeMons v. Regents of University of California. Comparative fault reduces the entire recovery by the plaintiff’s percentage share of blame for the accident itself; a plaintiff 20% at fault loses 20% across the board. Mitigation only removes the specific dollar amount of post-injury harm the plaintiff could have prevented. A jury can apply both doctrines in one case, but they answer different questions.²

A plaintiff can carry zero fault for the accident and still face a mitigation reduction for ignoring medical advice. A plaintiff partially at fault for the accident can avoid any mitigation reduction by diligently following a recovery plan.

Related Instructions to Know About

CACI 3930 covers personal injury damages generally, but two neighboring instructions handle situations a reader may actually be looking at.

CACI 3962 addresses future lost earnings. It tells the jury that a plaintiff cannot recover future wages the defendant proves the plaintiff can avoid losing by returning to work as soon as reasonably possible. The jury figures what the plaintiff would have earned in the pre-injury job, subtracts what the plaintiff can reasonably earn from alternative employment, and awards the difference. A plaintiff who is physically able to do some form of work but makes no effort to look risks losing the lost-earnings piece of the award.³

CACI 358 covers mitigation in contract cases rather than personal injury. The core idea is similar, but contract and tort damages follow different rules, so if the case involves a breach of contract instead of a physical injury, CACI 358 is the instruction that applies.⁴

1
Justia. CACI No. 3930 Mitigation of Damages (Personal Injury)
2
Justia Law. LeMons v. Regents of University of California
3
Justia. CACI No. 3962 Duty to Mitigate Damages for Future Lost Earnings
4
Justia. CACI No. 358 Mitigation of Damages