CACI 3930: Mitigation of Damages in Personal Injury

CACI 3930 is the California civil jury instruction on mitigation of damages in personal injury cases. It tells jurors that a plaintiff cannot collect for harm the defendant proves the plaintiff could have avoided through reasonable effort or spending after the injury, judged by what the plaintiff could do without undue risk or hardship. It also tells jurors to include, in the award, the reasonable amounts the plaintiff actually spent trying to limit the harm.¹

What the Instruction Requires

The instruction has two halves, and the second one often gets missed. The first half is the familiar one: if the defendant caused the injury, the plaintiff cannot recover damages the defendant proves the plaintiff could have avoided with reasonable efforts or expenditures, considering the circumstances the plaintiff actually faced.¹

The second half runs the other direction. If the plaintiff did take reasonable steps to reduce the harm, the jury’s award should include the reasonable amounts they spent doing so. Physical therapy copays, follow-up appointments, assistive devices, transportation to treatment — spending aimed at keeping the injury from getting worse is itself recoverable.¹

The Defendant Has to Prove the Failure

This is the detail that matters most in practice. The plaintiff does not have to prove they mitigated. Mitigation is an affirmative defense: the defendant raises it, the defendant puts on the evidence, and the defendant loses the argument if that evidence is thin.¹

California appellate courts have been consistent on this. In Jackson v. Yarbray, the court confirmed that while a plaintiff must prove the extent of injury caused by the defendant, the burden of showing the plaintiff failed to limit consequential damages falls on the defendant. No proof, no deduction.¹

Meeting that burden usually takes three things: medical expert testimony that specific treatment would have reduced the condition, employment or vocational evidence that the plaintiff could have returned to work sooner, and a clear link between the plaintiff’s inaction and a specific dollar amount of avoidable harm. Arguments that the plaintiff “should have done more,” without that supporting evidence, generally fail.

What Reasonable Effort Looks Like

The jury measures the plaintiff’s conduct against what a reasonably careful person would have done in the same circumstances. The standard is objective. It does not ask whether this particular plaintiff felt motivated to go to physical therapy; it asks whether a reasonable person in that situation would have gone.¹

In Christiansen v. Hollings, the court described the duty as one of “reasonable diligence” in caring for the injury. What qualifies depends on the facts, and no fixed rule requires the plaintiff to pursue any particular type of medical care.¹

In practice, juries look at what the treating doctors recommended, how consistently the plaintiff followed that advice, and what the plaintiff’s daily activities looked like after the injury. A plaintiff claiming debilitating back pain whose social media shows them waterskiing will have trouble. A plaintiff who attended most appointments and tried to follow the plan generally meets the standard, even without perfect compliance.

When a Plaintiff Is Excused

The instruction itself references action “without undue risk or hardship,” and California case law has given that phrase real teeth.¹

A plaintiff does not have to undergo a medical procedure that carries a significant chance of making things worse. Surgery with risks of paralysis, infection, or other serious complications falls within the undue-risk exception. The same goes for experimental treatments with uncertain outcomes. Declining a dangerous procedure is reasonable, and the defendant cannot pin the resulting disability on that refusal.

Severe pain is another recognized limit. A plaintiff is not required to endure ongoing suffering just to reduce the defendant’s bill. In Valle de Oro Bank v. Gamboa, the court emphasized that the mitigation rule does not apply where it would force the plaintiff to sacrifice important rights or endure impractical burdens.¹

Financial Inability

The instruction tells jurors to consider whether the plaintiff could act “without undue risk or hardship,” and California courts have long accepted that a plaintiff who genuinely cannot afford recommended treatment may be excused. The law does not require spending money you don’t have to repair someone else’s damage.¹

This is not automatic, though. In Valencia v. Shell Oil Co., the California Supreme Court held that a plaintiff who made no effort to raise the needed funds and offered no evidence of inability to pay could not lean on financial hardship. Some showing of actual inability is expected.

Returning to Work

When the claim includes ongoing lost wages, mitigation shifts from treatment to employment, and a companion instruction, CACI 3962, applies. It tells the jury that a plaintiff cannot recover future lost earnings the defendant proves the plaintiff can avoid by returning to work as soon as reasonably possible.²

The math under CACI 3962 is specific: the jury takes what the plaintiff would have earned from the pre-injury job and subtracts what the plaintiff can reasonably earn from alternative work. The difference is the recoverable loss.²

The standard is still reasonableness. A construction worker with a shattered knee is not expected to return to construction, but a jury might expect them to look at sedentary work or vocational retraining if a doctor clears them for it. A documented job search matters, because defense counsel will look for gaps.

How the Reduction Is Calculated

When the defendant proves a mitigation failure, the jury runs a two-step calculation. It first determines the total damages caused by the defendant. It then identifies the specific portion of those damages the plaintiff could have avoided, and subtracts that amount.¹

A concrete illustration. A plaintiff is awarded $150,000 for a back injury. The defendant proves that $30,000 of that resulted from the plaintiff skipping a prescribed physical therapy program that would have prevented the condition from worsening. The jury subtracts $30,000. The plaintiff takes home $120,000, and the defendant still owes everything else.

What this calculation does not do is reduce the award by a percentage, the way comparative negligence does. The reduction is a flat dollar amount tied to specific avoidable harm. If the defense evidence only links $5,000 of a $200,000 award to the plaintiff’s inaction, the reduction is $5,000, regardless of how unreasonable the behavior might look.

Mitigation Is Not Comparative Fault

These two doctrines get mixed up constantly, and the mix-up matters because they work differently. Comparative fault addresses the plaintiff’s negligence before or during the event that caused the injury. Mitigation addresses what the plaintiff did after the injury happened.³

The California Supreme Court drew that line in LeMons v. Regents of University of California. Comparative fault reduces the plaintiff’s entire recovery by a percentage reflecting their share of blame for the accident. Mitigation only removes the specific dollar amount of post-injury harm the plaintiff could have prevented. A jury can apply both in the same case, and they operate independently: a plaintiff with zero comparative fault can still face a mitigation reduction for ignoring medical advice, and a partially at-fault plaintiff who followed their recovery plan diligently will not face a mitigation hit at all.³

Related Instructions

CACI 3930 is the personal injury version. For future lost earnings specifically, CACI 3962 does the tailored calculation described above, and a judge may give both instructions in the same trial — 3930 for medical damages the plaintiff could have avoided, 3962 for wages the plaintiff could still earn.²

If the case is a breach of contract rather than a physical injury, CACI 3930 is the wrong instruction. The mitigation principle for contract cases lives in CACI 358, and while the core idea is similar, the language and context differ because tort damages and contract damages follow different rules.⁴

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