Loss of Chance: Wrongful Death from a Missed Diagnosis

Reviewed by Christopher Murphy, Esq. · Updated July 2026 · General information, not legal advice.

When someone you love dies after a doctor missed the warning signs, the hardest question is often the one that keeps you up at night: would they still be here if the cancer had been caught in the spring instead of the fall, or if someone had read the scan correctly the first time? For years, Massachusetts law had a brutal answer for many of those families. If the patient’s odds were already worse than even before the doctor’s mistake, the case was over before it started. That changed in 2008. This is a plain explanation of the “loss of chance” doctrine, what it does, and where it fits in a Massachusetts wrongful death case.

What “loss of chance” actually means

Loss of chance is a way of thinking about causation in a very specific kind of medical case. The idea is simple once you sit with it. A patient walks in with some percentage chance of surviving or of getting a better result. A doctor’s negligence, usually a missed or delayed diagnosis, knocks that percentage down. The lost chance itself is treated as a real, compensable injury, separate from the death.

That reframing matters because of how disease works. Cancer, heart disease, and stroke do not wait for a diagnosis. A patient with an aggressive tumor might have had, say, a below-even chance of surviving even with flawless care. Under the old thinking, a lawyer could never prove that the doctor’s mistake, rather than the underlying disease, was the thing that caused the death. The doctrine of loss of chance says the law should still care that the mistake took away part of whatever chance the patient had.

Massachusetts recognizes it: Matsuyama v. Birnbaum

The Supreme Judicial Court adopted loss of chance in Matsuyama v. Birnbaum, 452 Mass. 1 (2008). The facts are the kind trial lawyers see too often. A primary care doctor treated a patient’s stomach complaints over a period of years and did not catch the gastric cancer growing underneath them until it had spread and become untreatable. By the time of the correct diagnosis, the patient’s odds were gone.

The SJC held that a physician can be liable when negligence reduces or eliminates a patient’s chance of a more favorable outcome, and that this is true even when the patient’s chances were already less than even before the negligence happened. The Court was careful. It did not rewrite the rules for every kind of injury case. It recognized loss of chance specifically in the medical malpractice setting, where doctors are hired precisely to improve a patient’s odds and where reliable statistics about survival often exist. In Massachusetts, this is settled law, not a fringe theory.

Why the old all-or-nothing rule shut families out

Traditional negligence law runs on a coin-flip standard. You have to prove that, more likely than not, the defendant’s conduct caused the harm. More likely than not means better than fifty percent. That works fine for a broken leg. It falls apart for a patient who was already seriously ill.

Picture a patient who had a four-in-ten chance of surviving a cancer if it had been found on time. A doctor misses it, and the patient dies. Under the all-or-nothing rule, the family loses. They cannot show that the missed diagnosis, standing alone, more likely than not caused the death, because the disease itself already had the upper hand. The doctor’s negligence escapes accountability for the very reason the patient was vulnerable in the first place. The SJC called that result unfair, and it was. Loss of chance closes that gap without pretending the disease played no part.

How the damages work: proportional, not the full value

Here is the part families most often misunderstand, so read it slowly. Loss of chance does not let a family recover the full value of the death when the odds were already stacked against the patient. The recovery is proportional. It is tied to the size of the chance that was taken away, not to the entire loss.

The mechanics look roughly like this. A jury first decides what the full value of the death would be if this were an ordinary wrongful death case. Then it looks at the medical evidence: what was the patient’s chance of survival at the moment of the negligence, and what was it afterward? The difference, the slice of chance the negligence destroyed, becomes a percentage. The family recovers that percentage of the full value, and no more. A larger lost chance means a larger share. A smaller one means a smaller share.

Two honest points follow from that. First, these cases still demand real proof. You need expert testimony that can put credible numbers on the chance before and after the mistake, usually built from staging data and survival statistics. Second, no one can tell you what your claim is worth from a phone call. Value is built from the records, the expert opinions, and the specific facts, and you should be skeptical of anyone who quotes you a figure early. For how damages are measured in wrongful death generally, see our page on wrongful death damages in Massachusetts.

What these cases look like in real life

Loss of chance almost always grows out of a diagnosis that came late or never came at all. A few patterns show up again and again.

• The missed cancer. A lump, a bleed, an abnormal lab value, or a lingering symptom gets written off. Months or years pass. By the time the cancer is named, it has moved to a stage where cure is off the table. This is the classic missed diagnosis wrongful death scenario.
• The imaging that sat unread or was read wrong. A CT or MRI shows a small mass, a nodule, or an early bleed, and the finding is missed, misread, or never communicated to the patient. A delayed diagnosis in Massachusetts often traces back to a single radiology report that no one acted on.
• The heart attack or stroke sent home. Chest pain treated as indigestion, or stroke symptoms treated as a migraine or anxiety, so the patient loses the narrow window when clot-busting drugs or intervention could have changed everything.

The thread running through all of them is time. In each, earlier action would have given the patient a better fighting chance, and the delay took part of that chance away.

It is still a medical malpractice claim, and it faces the tribunal

A loss of chance case is a medical malpractice case. That means it carries the same procedural hurdle every med-mal claim in this state carries. Under M.G.L. c. 231, § 60B, the claim goes before a screening tribunal, made up of a judge, a physician, and an attorney, that reviews whether there is enough evidence to raise a legitimate question of malpractice rather than an unfortunate outcome.

In practice, that means you need a supportive expert early. A physician has to be willing to review the records and say, in substance, that the care fell below the accepted standard and that the failure cost the patient a real chance. If the tribunal is not satisfied, the case can still go forward, but only after posting a bond. This is one of several reasons these claims reward getting the records reviewed by qualified experts quickly instead of waiting.

How loss of chance fits inside a wrongful death claim

When the patient dies, the loss of chance theory rides inside a wrongful death claim brought under M.G.L. c. 229, § 2, the Massachusetts wrongful death statute. The executor or administrator of the estate brings the suit on behalf of the statutory beneficiaries, usually a spouse, children, or next of kin. The theory of causation is what makes it a loss of chance case; the wrongful death statute is the vehicle that carries it.

The doctrine also has its limits, and it is worth being straight about them. Loss of chance lives in the medical context, where survival odds can be measured. It is not a general escape hatch from having to prove causation in every negligence case. And it does not turn a bad result into a lawsuit on its own. Medicine involves risk, and not every death after a delayed diagnosis is malpractice. What the doctrine does is give families a fair path when a preventable delay stole a chance the patient actually had.

What to do if you think a delay cost your family member

Get the complete medical records, including the imaging and the radiology reports, and get them in front of someone who can read them critically. These cases turn on timelines and on expert review, and both take time to build. There are also deadlines that apply to medical malpractice and wrongful death claims, and they are not forgiving, so do not wait to have the file looked at.

Questions families ask

Can we still have a case if the odds were already bad?

Yes. That is the entire point of the loss of chance doctrine that Massachusetts adopted in Matsuyama v. Birnbaum. Even when the patient’s chance of survival was below even before the negligence, the family can recover for the portion of that chance the mistake took away.

Does loss of chance pay the full value of the death?

No. The recovery is proportional. It is a percentage of the full value, matched to the size of the chance that was lost, not the entire amount you would see in a straightforward wrongful death case.

Is a missed diagnosis automatically malpractice?

No. A bad outcome is not the same as negligence. The question is whether the care fell below the accepted standard and whether that failure cost the patient a real chance at survival or a better result. A qualified expert has to review the records and support that before the case can move forward under M.G.L. c. 231, § 60B.

Who brings the claim?

The estate does. The court appoints an executor or administrator, who files the wrongful death claim under M.G.L. c. 229, § 2 on behalf of the surviving family members the statute protects.

How fast do we need to move?

Soon. These cases depend on records and expert review, and strict deadlines apply to medical malpractice and wrongful death claims. Waiting can cost you the case before anyone reads the first page.

We handle these claims on a contingency basis, which means no fee unless we recover. If you think a missed or delayed diagnosis cost someone in your family their chance, call us at 617-415-2100.

Related guides

Who can file · What families recover · Deadlines · The claim process