Research/Causation and Damages in Massachusetts Injury Law
Causation and Damages in Massachusetts Injury Law
Every injury claim turns on two questions: did the other person’s negligence cause the harm, and what is that harm worth in law. This page sets out how Massachusetts courts answer both, in the words of the decisions themselves: twenty opinions of the Supreme Judicial Court and the Appeals Court, and the statutes that change the general rules.
Key findings
- Causation has two parts. The negligence must be a cause in fact of the harm, and the harm must fall within the foreseeable risk that made the conduct negligent.
- Since 2021, the test for cause in fact in most cases is “but for”: would the harm have happened without the negligence? The Supreme Judicial Court dropped the older “substantial factor” test in ordinary negligence cases, but left it in place for asbestos and other toxic tort cases.
- A defendant need not be the only cause. When several wrongdoers cause one injury that cannot be divided, each is liable for all of it, and one who pays more than an equal share can recover the excess from the others.
- A wrongdoer whose act worsens a condition the injured person already had is liable for the worsening. The Massachusetts opinions used here state that rule without using the phrase “eggshell plaintiff.”
- Damages cover pain and suffering, reasonable medical expenses and lost earning capacity, past and future. Punitive damages are allowed only where a statute expressly authorizes them, as the wrongful death statute does.
- In medical malpractice, a lost chance of a better outcome is itself an injury, and damages are limited to the part of the loss the negligence destroyed.
How this page was put together
Each rule on this page comes from a court opinion or a statute read in full. The opinions were read on CourtListener and the statutes on the Massachusetts Legislature’s website. A script checked every quotation on the page, word for word, against the saved text of its source before the page was built.
Short definitions of many of the terms below are in the Massachusetts injury law glossary.
Left out, and why:
- Dollar amounts. Some statutes set limits or thresholds in dollars; this page describes them without the figures.
- Model jury instructions, which this page did not read. Where a court describes an instruction, the page quotes the court.
- Federal law, and the special rules for workers’ compensation benefits, except where a case on this page decided a general question.
- Every later case. Some decisions here are old; each is used only for the rule quoted from it.
What this page covers
- Decisions of the Supreme Judicial Court from 1908 to 2025 and of the Appeals Court from 1998 to 2012.
- Massachusetts General Laws chapters 229, 231 and 231B as published on the Legislature’s website.
- Negligence claims for personal injury and death.
- Law checked November 3, 2026. This is a summary of published law, not advice about any case.
Causation is two questions, not one
The first question is factual. In Doull v. Foster (2021), the Supreme Judicial Court put it this way: “Generally, a defendant is a factual cause of a harm if the harm would not have occurred ‘but for’ the defendant’s negligent conduct.”
The second is legal. “The law does not impose liability for all harm factually caused by tortious conduct,” the court said in Leavitt v. Brockton Hospital (2009). “Liability for conduct obtains only where the conduct is both a cause in fact of the injury and where the resulting injury is within the scope of the foreseeable risk arising from the negligent conduct.” The court there called this the “scope of liability,” the question older cases call proximate cause, and in Kent v. Commonwealth (2002) it described proximate cause as depending on whether the injury was a “foreseeable result of the defendant’s negligent conduct”.
So a defendant can be a cause in fact and still not be liable, if the harm was not the kind of harm that made the conduct careless in the first place. See also “proximate cause” in the glossary.
What changed in 2021
Before 2021, Massachusetts courts also used a “substantial factor” test for cause in fact. In Doull v. Foster, a medical malpractice case, the Supreme Judicial Court ended that: “we conclude that the substantial factor test is unnecessarily confusing and discontinue its use, even in multiple sufficient cause cases.” It held that “the traditional but-for factual causation standard is the appropriate standard to be employed in most cases, including those involving multiple alleged causes.”
Three points from the decision matter in practice. First, “there is no requirement that a defendant must be the sole factual cause of a harm.” Second, in the rare case where two causes act at once and either alone would have caused the whole harm, the court’s example being two fires that merge and destroy a house, “the jury do not have to make a but-for causation finding.” Third, the court left the old instruction in place for one group of cases: “we do not disturb our decision in O’Connor or the use of the substantial contributing factor instruction in those cases”, referring to toxic tort and asbestos cases, and said it may revisit that later.
The court repeated the test in Luppold v. Hanlon (2025), another malpractice case, quoting Doull that “a but-for standard, rather than a substantial factor standard, is the appropriate standard for factual causation.” It approved a trial judge’s plain-language version, which asked the jury: “did the negligence make a difference?”
When something else happens in between
Harm often follows a chain of events. “If a series of events occur between the negligent conduct and the ultimate harm, the court must determine whether those intervening events have broken the chain of factual causation or, if not, have otherwise extinguished the element of proximate cause and become a superseding cause of the harm,” the court said in Kent v. Commonwealth. A later event that does that is a superseding cause, and it relieves the first wrongdoer of liability.
In Kent, the parole board released a prisoner to federal immigration custody for deportation, and eight years later he shot a Leominster police officer. The court held that the immigration service’s later release of him in Massachusetts “became a superseding cause of the harm he inflicted”, so the Commonwealth was not liable as a matter of law.
When more than one person is to blame
Massachusetts keeps joint and several liability. When the acts of two or more wrongdoers operate together “so that in effect the damages suffered are rendered inseparable,” “they are jointly and severally liable,” the court said in O’Connor v. Raymark Industries (1988), quoting an earlier case. In Shantigar Foundation v. Bear Mountain Builders (2004) it put the consequence plainly: “a plaintiff injured by more than one tortfeasor may sue any or all of them for her full damages.”
Among the wrongdoers, the court explained, those who pay more than their “‘pro rata’ (equal)” share may seek contribution from the others. Under G. L. c. 231B, § 1, one who “has paid more than his pro rata share of the common liability” may recover the excess, and “No tortfeasor shall be compelled to make contribution beyond his own pro rata share of the entire liability.”
The injured person’s own carelessness is weighed separately. Under G. L. c. 231, § 85, it does not bar recovery “if such negligence was not greater than the total amount of negligence attributable to the person or persons against whom recovery is sought”, but “any damages allowed shall be diminished in proportion to the amount of negligence attributable to the person for whose injury, damage or death recovery is made.” See “comparative negligence” in the glossary.
When an injury worsens a condition someone already had
Some people already have an illness or an old injury when a negligent act makes it worse. The rule for that comes from Wallace v. Ludwig (1935): “If the injury causes or contributes to cause the development of a preexisting disease, the person liable for the injury is liable also for the resulting aggravation.” “The wrongdoer may be held responsible for the harmful results of the combined effects of his wrongful act and the disease.”
This is the idea often searched for as the eggshell plaintiff rule. None of the Massachusetts opinions read for this page uses the word “eggshell”; they speak of aggravating a preexisting condition.
The rule fixes what the wrongdoer pays for, not whether the wrongdoer caused it. In Higgins v. Delta Elevator Service Corp. (1998), a woman said she tripped and fell leaving an elevator that did not level properly, and that the fall worsened her multiple sclerosis. The judge told the jury that the measure was “the difference at any given time between what the plaintiff’s condition would have been absent the accident and what the plaintiff’s condition is or was or will be because of the accident”. The Appeals Court found that instruction “substantially correct”, and upheld the verdict, in which the jury found the elevator company negligent but its negligence not a direct cause of a worsening of her disease.
What damages are meant to cover
The court listed the main categories in Rodgers v. Boynton (1943). An injured person is entitled to recover “for pain and suffering; for reasonable expenses incurred by him for medical care and nursing in the treatment and cure of his injury; for diminution in his earning power;” and “for such pain and suffering and such expenses and diminution of earning capacity as are shown to be reasonably probable to continue in the future.” “The measure of damages is fair compensation for the injury sustained.”
Four points fill that in.
- Pain and suffering, past and future. Damages must fairly compensate for “the physical pain and the mental suffering, both that undergone in the past and likely to occur in the future”, the court said in Cuddy v. L & M Equipment Co. (1967), where it held that life expectancy was “clearly relevant on the issue of the degree of expected future pain and suffering.”
- Earning capacity, not only wages. In Corsetti v. Stone Co. (1985) the court said the judge correctly instructed the jury that the plaintiff “was entitled to recover for lost earning capacity.” An injured person who was not working for pay is covered too: “Whether she was gainfully employed or not at the time of the injury, she was entitled to damages for any impairment in her capacity to work and earn.” (Rodgers).
- Medical expenses at their reasonable value. In Law v. Griffith (2010) the court held that “medical bills are admissible to establish the reasonable value of services rendered where the services are related to the injury for which the claim is made” and that evidence of “the range of payments accepted by medical providers as payment in full” is also admissible on the reasonable value of the care.
- Future losses need proof, not precision. The plaintiff must prove damages “with reasonable certainty”, but “Evidence that enables the jury to arrive at an approximate estimate of damages is sufficient”, the Appeals Court said in Coady v. Wellfleet Marine Corp. (2004), a case about a boat slip rather than an injury, which also noted that in personal injury cases “compensation for future lost wages will be treated conceptually as an already incurred loss of earning capacity”.
Statutes adjust these rules in some cases:
- In a motor vehicle injury case, G. L. c. 231, § 6D allows damages for pain and suffering only if reasonable and necessary medical expenses exceed a set amount, or the injury causes death, the loss of a body member, permanent and serious disfigurement, certain losses of sight or hearing, or “consists of a fracture.” See the glossary entry.
- In a malpractice case against a health care provider, G. L. c. 231, § 60H limits damages “for pain and suffering, loss of companionship, embarrassment and other items of general damages” to a set amount, unless the jury finds “a substantial or permanent loss or impairment of a bodily function or substantial disfigurement” or other special circumstances. See the glossary entry.
- Under G. L. c. 231, § 6B, the clerk adds interest to damages for personal injuries “at the rate of twelve per cent per annum from the date of commencement of the action”. See “prejudgment interest”.
- Payments from other sources generally do not reduce the award. Ordinarily, the court said in Corsetti, “a defendant may not show that the plaintiff has received other compensation for his injury, whether from an accident insurance policy” or other sources. See “collateral source rule”. Malpractice cases follow a separate statute; see “collateral source reduction”.
The duty to keep the harm from growing
An injured person has to act reasonably after the injury. “A party injured by a tort has a duty to use reasonable care to minimize the damages”, the court said in Brian v. B. Sopkin & Sons (1943), a case about damaged goods. An older case applied the same idea to an injured street railway passenger: “It was the duty of the plaintiff, not only to do nothing to aggravate the results of the accident, but to use all reasonable care to lessen the injurious effects of what had happened” (Sullivan v. Old Colony Street Railway, 1908).
Punitive damages need a statute
Massachusetts does not award punitive damages as a general matter. “Punitive damages are not allowed in this Commonwealth unless expressly authorized by statute”, the court said in Flesner v. Technical Communications Corp. (1991).
The wrongful death statute is one that does. G. L. c. 229, § 2 allows punitive damages, in at least a minimum amount it sets, where the death was caused by “the malicious, willful, wanton or reckless conduct of the defendant or by the gross negligence of the defendant”. See the glossary entry.
Proving causation with an expert
Many injuries need a doctor to explain the link. “Expert testimony is necessary where proof of medical causation lies outside the ken of lay jurors,” the Appeals Court said in Pitts v. Wingate at Brighton (2012). “However, where a determination of causation lies within ‘general human knowledge and experience,’ expert testimony is not required.” In that case a nursing home resident’s fall to the floor was “an obvious, commonsense explanation” for her injuries, and no expert was needed.
When an expert does testify, the judge screens the science first. In Commonwealth v. Lanigan (1994) the Supreme Judicial Court said: “We suspect that general acceptance in the relevant scientific community will continue to be the significant, and often the only, issue.” It added that a party “may demonstrate the reliability or validity of the underlying scientific theory or process by some other means, that is, without establishing general acceptance.”
That screening applies to injury cases. In Higgins v. Delta Elevator Service Corp. (1998), the Appeals Court said the judge “must play a ‘gatekeeper’ role in determining whether to admit such evidence.” And in Canavan’s Case (2000), the Supreme Judicial Court held that a treating doctor’s opinion on causation is not exempt: “There is no logical reason why conclusions based on personal observations or clinical experience should not be subject to the Lanigan analysis.”
A lost chance in a medical case
Sometimes a patient’s odds were already poor, and a doctor’s negligence made them worse. In Matsuyama v. Birnbaum (2008), a cancer case, the Supreme Judicial Court held: “Where a physician’s negligence reduces or eliminates the patient’s prospects for achieving a more favorable medical outcome, the physician has harmed the patient and is liable for damages.”
The court was careful about what kind of rule this is: “Thus we recognize loss of chance not as a theory of causation, but as a theory of injury.” The patient must still prove, by a preponderance of the evidence, that “the physician’s negligence caused the plaintiff’s likelihood of achieving a more favorable outcome to be diminished.”
Damages are proportional. The court’s formula “aims to ensure that a defendant is liable in damages only for the monetary value of the portion of the decedent’s prospects that the defendant’s negligence destroyed.” And the court said “our decision today is limited to loss of chance in medical malpractice actions.”
The cases on this page
| Case | Court and year | Cited for |
|---|---|---|
| Doull v. Foster, 487 Mass. 1 (2021) | Supreme Judicial Court, 2021 | But-for test for cause in fact; “substantial factor” dropped except in toxic tort cases |
| Luppold v. Hanlon, 495 Mass. 148 (2025) | Supreme Judicial Court, 2025 | Restates the Doull test |
| Leavitt v. Brockton Hospital, Inc., 454 Mass. 37 (2009) | Supreme Judicial Court, 2009 | Scope of liability: harm within the foreseeable risk |
| Kent v. Commonwealth, 437 Mass. 312 (2002) | Supreme Judicial Court, 2002 | Proximate cause; superseding cause |
| O’Connor v. Raymark Industries, Inc., 401 Mass. 586 (1988) | Supreme Judicial Court, 1988 | Joint and several liability |
| Shantigar Foundation v. Bear Mountain Builders, 441 Mass. 131 (2004) | Supreme Judicial Court, 2004 | Joint and several liability kept; contribution |
| Wallace v. Ludwig, 292 Mass. 251 (1935) | Supreme Judicial Court, 1935 | Liability for aggravating a preexisting condition |
| Higgins v. Delta Elevator Service Corp., 45 Mass. App. Ct. 643 (1998) | Appeals Court, 1998 | Measure of damages for an aggravated condition; judge as gatekeeper |
| Rodgers v. Boynton, 315 Mass. 279 (1943) | Supreme Judicial Court, 1943 | Categories of personal injury damages |
| Cuddy v. L & M Equipment Co., 352 Mass. 458 (1967) | Supreme Judicial Court, 1967 | Future pain and suffering; life expectancy |
| Corsetti v. Stone Co., 396 Mass. 1 (1985) | Supreme Judicial Court, 1985 | Lost earning capacity; collateral source rule |
| Law v. Griffith, 457 Mass. 349 (2010) | Supreme Judicial Court, 2010 | Reasonable value of medical care |
| Coady v. Wellfleet Marine Corp., 62 Mass. App. Ct. 237 (2004) | Appeals Court, 2004 | Reasonable certainty of damages (not an injury case) |
| Brian v. B. Sopkin & Sons, Inc., 314 Mass. 180 (1943) | Supreme Judicial Court, 1943 | Duty to minimize damages |
| Sullivan v. Old Colony Street Railway, 200 Mass. 303 (1908) | Supreme Judicial Court, 1908 | Duty to lessen the effects of an injury |
| Flesner v. Technical Communications Corp., 410 Mass. 805 (1991) | Supreme Judicial Court, 1991 | Punitive damages only by statute |
| Commonwealth v. Lanigan, 419 Mass. 15 (1994) | Supreme Judicial Court, 1994 | Screening of scientific evidence |
| Canavan’s Case, 432 Mass. 304 (2000) | Supreme Judicial Court, 2000 | Screening applies to a treating doctor’s causation opinion |
| Pitts v. Wingate at Brighton, Inc., 82 Mass. App. Ct. 285 (2012) | Appeals Court, 2012 | When an expert is needed on causation |
| Matsuyama v. Birnbaum, 452 Mass. 1 (2008) | Supreme Judicial Court, 2008 | Loss of chance in medical malpractice |
Citations as reported. Older decisions are used only for the rule quoted. Opinions read on CourtListener, November 3, 2026.
What this page cannot tell you
- How any one case will come out. That depends on the evidence in that case.
- Rules for workers’ compensation benefits, government defendants and other special settings, which have their own statutes.
- Later changes. The law is stated as of November 3, 2026; courts and the Legislature can change it.
- The dollar amounts in the statutes mentioned. Those are on the Legislature’s website, linked above.
Proof of harm is half of every claim
Fault gets most of the attention in an injury case, but a claim also has to show what the negligence caused and what that harm is worth. These rules decide both, and they apply whether the injury came from a crash, a fall or a medical error.
Related research on this site covers crash injuries and deaths, injury-related hospital stays and the Massachusetts injury law glossary.
Citing this page
Larson Law Boston, “Causation and Damages in Massachusetts Injury Law,” published November 3, 2026. Law checked November 3, 2026.
This page may be quoted with attribution and a link to this page. Press and research inquiries: marketing@dlarsonlaw.com
Sources
- Massachusetts Legislature, General Laws, Chapter 231, Section 85 (comparative negligence) (archived copy; official page: https://malegislature.gov/Laws/GeneralLaws/PartIII/TitleII/Chapter231/Section85). Read November 3, 2026.
- Massachusetts Legislature, General Laws, Chapter 231B, Section 1 (contribution) (archived copy; official page: https://malegislature.gov/Laws/GeneralLaws/PartIII/TitleII/Chapter231B/Section1). Read November 3, 2026.
- Massachusetts Legislature, General Laws, Chapter 229, Section 2 (wrongful death damages) (archived copy; official page: https://malegislature.gov/Laws/GeneralLaws/PartIII/TitleII/Chapter229/Section2). Read November 3, 2026.
- Massachusetts Legislature, General Laws, Chapter 231, Section 6D (pain and suffering in motor vehicle cases) (archived copy; official page: https://malegislature.gov/Laws/GeneralLaws/PartIII/TitleII/Chapter231/Section6D). Read November 3, 2026.
- Massachusetts Legislature, General Laws, Chapter 231, Section 60H (malpractice limit) (archived copy; official page: https://malegislature.gov/Laws/GeneralLaws/PartIII/TitleII/Chapter231/Section60H). Read November 3, 2026.
- Massachusetts Legislature, General Laws, Chapter 231, Section 6B (interest) (archived copy; official page: https://malegislature.gov/Laws/GeneralLaws/PartIII/TitleII/Chapter231/Section6B). Read November 3, 2026.
- CourtListener (Free Law Project), Full text of the twenty opinions listed in the table above. Read November 3, 2026.
If you were hurt and have questions
These pages explain what the public record shows. They are not advice about a specific situation, and what applies to a particular case depends on its facts. If something here raises a question about your own circumstances, you are welcome to get in touch.
