Causation in Pennsylvania and New Jersey Tort Law

Causation in Pennsylvania and New Jersey Tort LawCause-in-Fact, Proximate Cause, and the Substantial Factor Test

Posted By Brian E. Fritz, Esquire | Fritz and Bianculli, LLC | Philadelphia, PA

Introduction

Causation is the third essential element of a negligence claim, following duty and breach. Even where a plaintiff establishes that the defendant owed a duty of care and breached that duty, the claim fails unless the plaintiff can prove that the defendant’s breach caused the plaintiff’s injuries. Causation thus serves as the critical link between the defendant’s wrongful conduct and the harm for which the plaintiff seeks compensation.¹

Pennsylvania and New Jersey both recognize that causation comprises two distinct inquiries: cause-in-fact (also called actual cause or “but-for” causation) and proximate cause (also called legal cause). Cause-in-fact asks whether the defendant’s conduct was a necessary antecedent to the plaintiff’s harm—whether the harm would have occurred “but for” the defendant’s breach. Proximate cause asks whether the connection between the defendant’s conduct and the plaintiff’s harm is sufficiently close, direct, and foreseeable to justify the imposition of liability as a matter of law and policy.²

This article examines the causation element in depth, tracing its doctrinal development in Pennsylvania and New Jersey, analyzing the tests that courts apply, and exploring the special causation problems that arise in toxic tort, medical malpractice, and multi-defendant litigation. Throughout, particular attention is given to how these principles operate in cases arising in the Philadelphia region and South Jersey, where industrial history, urban density, and access to major medical centers create a distinctive litigation landscape.

Part One: Cause-in-Fact

A. The But-For Test

The foundational test for cause-in-fact is the “but-for” test: the plaintiff must prove that, but for the defendant’s negligent conduct, the harm would not have occurred. This inquiry is fundamentally factual—it asks whether the defendant’s breach was a necessary condition of the plaintiff’s injury.³

Pennsylvania applies the but-for test as the default standard for establishing cause-in-fact. In Whitner v. Lojeski (1970), the Pennsylvania Supreme Court confirmed that a plaintiff must demonstrate that the harm would not have occurred absent the defendant’s negligence. The burden rests with the plaintiff to prove causation by a preponderance of the evidence—that is, to show that it is more likely than not that the defendant’s conduct caused the harm.⁴

New Jersey similarly applies the but-for test as its primary causation standard. In Scafidi v. Seiler (1990), the New Jersey Supreme Court articulated the requirement that the plaintiff prove the defendant’s negligence was a cause-in-fact of the injury, meaning the injury would not have occurred without the negligent conduct.⁵

The but-for test works well in straightforward cases. If a driver runs a red light and strikes a pedestrian, the but-for inquiry is simple: but for the driver’s failure to stop, the pedestrian would not have been struck. Similarly, if a property owner fails to repair a broken stair and a visitor falls, the causal connection between the breach and the harm is direct and easily established.

However, the but-for test encounters significant difficulties in cases involving multiple causes, concurrent tortfeasors, or uncertain causal mechanisms. These complexities have led courts to develop supplementary tests, most notably the substantial factor test.

B. The Substantial Factor Test

Where the but-for test proves inadequate—particularly in cases involving multiple sufficient causes—Pennsylvania and New Jersey courts apply the substantial factor test. Under this test, the plaintiff must prove that the defendant’s conduct was a substantial factor in bringing about the harm, even if other causes also contributed.⁶

The substantial factor test originated in the Restatement (Second) of Torts § 431, which Pennsylvania has adopted. The test asks whether the defendant’s conduct was of sufficient significance in producing the harm to warrant the imposition of liability. A factor is “substantial” if it is not so insignificant that no reasonable person would consider it a cause of the harm.⁷

Pennsylvania embraced the substantial factor test in cases where multiple causes combine to produce an indivisible injury. In Gradel v. Inouye (1980), the Pennsylvania Supreme Court held that where two or more causes concur to produce an injury, and either alone would have been sufficient to cause the harm, each tortfeasor may be held liable if their conduct was a substantial factor in producing the result.⁸

New Jersey likewise applies the substantial factor test in appropriate circumstances. In Conklin v. Hannoch Weisman (1996), the New Jersey Supreme Court explained that the substantial factor test is particularly appropriate in cases involving concurrent causes, where strict application of the but-for test would permit each defendant to escape liability by pointing to the other’s conduct.⁹

1. Application to Concurrent Tortfeasors

The substantial factor test is essential in cases involving concurrent tortfeasors—multiple defendants whose independent acts combine to cause a single, indivisible harm. Consider a motor vehicle collision at the intersection of Broad Street and Walnut Street in Center City Philadelphia, in which two drivers simultaneously run red lights from different directions and both strike the plaintiff’s vehicle. Under a strict but-for analysis, each driver might argue that the other driver’s conduct alone was sufficient to cause the harm. The substantial factor test prevents this evasion of responsibility by asking whether each defendant’s conduct was a substantial contributing factor to the plaintiff’s injuries.

Pennsylvania courts have consistently applied the substantial factor test in multi-vehicle collision cases, construction site accidents involving multiple contractors, and premises liability cases where multiple parties contributed to a hazardous condition. In the Philadelphia region, where dense urban traffic and complex construction projects create frequent opportunities for concurrent negligence, the substantial factor test is a routine feature of causation analysis.¹⁰

2. Application to Toxic Tort and Occupational Exposure Cases

The substantial factor test takes on particular importance in toxic tort and occupational exposure cases, where plaintiffs may have been exposed to harmful substances from multiple sources over extended periods. Philadelphia’s industrial heritage—including shipyards, refineries, manufacturing facilities along the Delaware River, and the former Navy Yard—has generated substantial litigation involving asbestos, benzene, and other hazardous substances.¹¹

In Gregg v. V-J Auto Parts Co. (2007), the Pennsylvania Supreme Court addressed causation in asbestos litigation, holding that the plaintiff must prove that exposure to the defendant’s asbestos-containing product was a substantial factor in causing the plaintiff’s disease. The court rejected the argument that mere exposure was sufficient, requiring proof that the exposure was of sufficient magnitude and duration to constitute a substantial contributing cause.¹²

New Jersey has similarly developed extensive case law on toxic tort causation. In Sholtis v. American Cyanamid Co. (1989), the Appellate Division addressed the evidentiary requirements for proving causation in chemical exposure cases, emphasizing that expert testimony must establish both general causation (that the substance is capable of causing the type of harm alleged) and specific causation (that the substance caused this plaintiff’s harm).¹³

C. The Increased Risk and Lost Chance Doctrines

Traditional causation doctrine requires the plaintiff to prove that the defendant’s negligence more likely than not caused the harm. But what if the defendant’s negligence increased the risk of harm without definitively causing it, or deprived the plaintiff of a chance of a better outcome? Pennsylvania and New Jersey have grappled with these questions through the doctrines of increased risk and lost chance.

1. Increased Risk of Future Harm

In some cases, the defendant’s negligence exposes the plaintiff to an increased risk of future harm that has not yet materialized. Pennsylvania has permitted recovery for increased risk in limited circumstances, particularly where the risk is quantifiable and substantial. In Simmons v. Pacor, Inc. (1996), the Pennsylvania Supreme Court addressed claims for medical monitoring by plaintiffs exposed to asbestos, recognizing that exposure to a toxic substance may warrant recovery for the cost of monitoring even before disease manifests.¹⁴

New Jersey has likewise recognized claims for medical monitoring in appropriate toxic exposure cases. In Ayers v. Township of Jackson (1987), the New Jersey Supreme Court held that plaintiffs exposed to toxic contamination may recover the cost of medical surveillance necessary to detect the onset of disease, even though they have not yet developed a compensable injury.¹⁵

2. Lost Chance Doctrine in Medical Malpractice

The lost chance doctrine addresses situations where a defendant’s negligence reduces the plaintiff’s chance of a better outcome—typically, where a physician’s failure to diagnose or treat a condition reduces the patient’s chance of survival or recovery. Traditional causation principles would deny recovery unless the plaintiff could prove that, more likely than not, the negligence caused the ultimate harm. But this approach may leave patients without a remedy where the negligence demonstrably reduced their chances, even if the pre-existing condition was already more likely than not to result in death or serious harm.¹⁶

Pennsylvania has not adopted the lost chance doctrine. In Hamil v. Bashline (1978), the Pennsylvania Supreme Court required plaintiffs in medical malpractice cases to prove that the defendant’s negligence, with a reasonable degree of medical certainty, was a substantial factor in bringing about the harm. Subsequent Pennsylvania decisions have declined to adopt a pure lost chance approach, requiring plaintiffs to prove that proper treatment more likely than not would have achieved a better outcome.¹⁷

New Jersey, by contrast, has embraced the lost chance doctrine. In Scafidi v. Seiler (1990), the New Jersey Supreme Court held that a patient may recover for lost chance of survival where the physician’s negligence reduced the patient’s chance of survival, even if that chance was less than fifty percent. The court recognized lost chance as a compensable injury in itself, permitting recovery proportional to the chance that was lost.¹⁸

This divergence between Pennsylvania and New Jersey has significant practical implications for medical malpractice cases in the Philadelphia region. A patient treated at a Philadelphia hospital whose cancer diagnosis is delayed may face a higher causation burden than a patient treated across the Delaware River in Camden or Cherry Hill. Practitioners handling cases in this bistate market must be attentive to the choice of law implications that flow from this doctrinal difference.

D. Proof of Causation and Expert Testimony

In many personal injury cases, the causal connection between the defendant’s conduct and the plaintiff’s harm is not self-evident and must be established through expert testimony. This is particularly true in medical malpractice, toxic tort, and product liability cases, where specialized knowledge is required to explain how the defendant’s breach produced the plaintiff’s injuries.

1. Pennsylvania Standards

Pennsylvania requires that expert testimony on causation be stated with a “reasonable degree of medical certainty” or “reasonable degree of scientific certainty,” depending on the field. This formulation requires more than speculation or possibility—the expert must opine that the causal connection is more probable than not.¹⁹

Pennsylvania courts have excluded expert testimony that relies on methodology that is not generally accepted in the scientific community or that leaps from general scientific principles to specific causation without adequate foundation. In Betz v. Pneumo Abex LLC (2012), the Supreme Court emphasized that expert testimony on causation must be grounded in reliable methodology and must bridge the gap between general causation (can this type of exposure cause this type of harm?) and specific causation (did this exposure cause this plaintiff’s harm?).²⁰

2. New Jersey Standards

New Jersey applies similar requirements for expert testimony on causation. Under the standard articulated in Rubanick v. Witco Chemical Corp. (1991), expert testimony must be based on scientifically reliable methodology, and the expert must be able to articulate a sound basis for the opinion that the defendant’s conduct caused the plaintiff’s injury.²¹

New Jersey courts have shown some flexibility in toxic tort cases, recognizing that scientific certainty may be elusive and that requiring absolute proof would effectively immunize defendants whose products cause harm through complex biological mechanisms. In Landrigan v. Celotex Corp. (1992), the New Jersey Supreme Court permitted expert testimony based on reasonable scientific inference, even where epidemiological studies could not definitively establish causation for the specific plaintiff.²²

Part Two: Proximate Cause

A. The Concept of Legal Cause

Even where cause-in-fact is established, the plaintiff must also prove proximate cause—sometimes called legal cause. Proximate cause is a policy-based limitation on liability that asks whether the connection between the defendant’s conduct and the plaintiff’s harm is sufficiently direct and foreseeable to justify imposing liability. It reflects the judgment that not all consequences that flow from a defendant’s negligence should be compensable, even if the but-for or substantial factor test is satisfied.²³

Pennsylvania and New Jersey both frame proximate cause in terms of foreseeability. The question is whether the harm that occurred was a reasonably foreseeable consequence of the defendant’s negligent conduct. If the harm was unforeseeable, or if the chain of causation was broken by an unforeseeable intervening event, proximate cause may be lacking even though cause-in-fact is established.²⁴

B. The Foreseeability Standard

Foreseeability is the cornerstone of proximate cause analysis in both Pennsylvania and New Jersey. A defendant is liable for the reasonably foreseeable consequences of their negligence, but not for consequences that could not reasonably have been anticipated.

1. Pennsylvania Approach

Pennsylvania applies the foreseeability test as articulated in the Restatement (Second) of Torts. In Commonwealth v. Rementer (1991), the Pennsylvania Superior Court explained that proximate cause requires a determination that the defendant’s conduct was a substantial factor in bringing about the harm and that the harm was a foreseeable consequence of the conduct. The defendant need not foresee the precise manner in which the harm occurs, but the general type of harm must have been within the scope of foreseeable risk.²⁵

Pennsylvania courts have emphasized that foreseeability is ordinarily a question for the jury. In Ford v. Jeffries (1977), the Supreme Court reiterated that proximate cause is typically a factual issue to be resolved by the trier of fact, unless the causal chain is so attenuated or the intervening cause so extraordinary that no reasonable jury could find proximate cause.²⁶

2. New Jersey Approach

New Jersey similarly grounds proximate cause in foreseeability. In Hill v. Yaskin (1977), the New Jersey Supreme Court held that a defendant is liable for all foreseeable consequences of their negligence, and that foreseeability is to be determined from the perspective of a reasonable person in the defendant’s position at the time of the negligent conduct.²⁷

New Jersey courts have been somewhat generous in finding foreseeability, recognizing that precise foreknowledge of the mechanism of harm is not required. In Davis v. Brooks (1993), the court held that a defendant who creates a foreseeable risk of harm is liable even if the precise sequence of events that produced the harm was not anticipated.²⁸

C. Intervening and Superseding Causes

A central issue in proximate cause analysis is whether an intervening cause—an event occurring after the defendant’s negligence and contributing to the plaintiff’s harm—breaks the chain of causation and relieves the defendant of liability. Pennsylvania and New Jersey both recognize the distinction between intervening causes that do not relieve the defendant of liability and superseding causes that do.

1. Intervening Causes

An intervening cause is any cause that comes into operation after the defendant’s negligence and contributes to the plaintiff’s harm. Not all intervening causes break the causal chain. If the intervening cause was foreseeable, or if the defendant’s negligence created the very risk that the intervening cause would occur, the defendant remains liable.²⁹

In Pennsylvania, the Supreme Court in Powell v. Drumheller (1995), held that an intervening act does not break the causal chain if it is a normal response to the situation created by the defendant’s negligence or if the defendant’s negligence created the risk that the intervening act would occur.³⁰

New Jersey applies a similar standard. In Lynch v. Scheininger (2000), the New Jersey Supreme Court explained that an intervening act will not break the causal chain if the act was reasonably foreseeable or if the defendant’s negligence created an unreasonable risk that such an act would occur.³¹

2. Superseding Causes

A superseding cause is an intervening cause that is so extraordinary, unforeseeable, or attenuated from the defendant’s negligence that it breaks the causal chain and relieves the defendant of liability. The superseding cause doctrine recognizes that at some point, the connection between the defendant’s conduct and the plaintiff’s harm becomes too remote to justify imposing liability.³²

In Pennsylvania, a superseding cause must be an event that was not reasonably foreseeable and that produces harm different in kind from that which would have resulted from the defendant’s negligence. The Pennsylvania Supreme Court in Vattimo v. Lower Bucks Hospital, Inc. (1985) held that an intervening act of medical malpractice does not constitute a superseding cause where the original tortfeasor’s negligence created the need for medical treatment, since medical malpractice is a foreseeable risk of requiring medical care.³³

New Jersey takes a similar approach. State v. Pelham (2003), the Supreme Court held that an intentional criminal act may constitute a superseding cause only if it was not reasonably foreseeable. Where the defendant’s negligence creates the opportunity for criminal conduct—for example, inadequate security in a high-crime area—the criminal act does not relieve the defendant of liability.³⁴

3. Third-Party Criminal Acts

A recurring issue in proximate cause analysis is whether a third party’s criminal conduct constitutes a superseding cause. This issue frequently arises in premises liability cases, particularly in urban environments where property owners may be charged with a duty to protect against foreseeable criminal acts.

In the Philadelphia region, cases involving inadequate security at apartment complexes, shopping centers, parking garages, and SEPTA stations regularly raise the question of whether criminal acts by third parties break the causal chain. Pennsylvania courts have generally held that foreseeable criminal conduct does not constitute a superseding cause, particularly where the defendant’s negligence consists of a failure to protect against the very risk of criminal activity.³⁵

New Jersey applies the same principle. In Clohesy v. Food Circus Supermarkets, Inc. (1997), the New Jersey Supreme Court held that a property owner may be liable for injuries caused by third-party criminal acts if the criminal conduct was a foreseeable consequence of the owner’s failure to provide adequate security.³⁶

D. The Eggshell Plaintiff Rule

The “eggshell plaintiff” rule—also known as the “thin skull” rule—holds that a defendant takes the plaintiff as they find them. If the defendant’s negligence aggravates a pre-existing condition or causes greater harm than would have occurred to a person without the plaintiff’s particular vulnerability, the defendant is liable for the full extent of the harm.

Pennsylvania has long recognized the eggshell plaintiff rule. In Fretts v. Pavetti (1980), the court determined that a defendant is liable for all harm proximately caused by their negligence, including harm that is more severe because of the plaintiff’s pre-existing susceptibility. The plaintiff’s vulnerability does not reduce the defendant’s liability; it increases it.³⁷

New Jersey likewise applies the eggshell plaintiff rule. In Fosgate v. Corona (1974), the Supreme Court confirmed that a tortfeasor is responsible for all damages flowing from their negligence, even if the plaintiff’s injuries are more severe than would have occurred in a person of ordinary health.³⁸

The eggshell plaintiff rule has significant practical implications in the Philadelphia and New Jersey market, where industrial exposure and urban environmental factors may leave plaintiffs with pre-existing vulnerabilities. A plaintiff with pre-existing respiratory compromise from prior occupational exposure may suffer greater harm from a subsequent toxic exposure than a healthy individual. Under the eggshell plaintiff rule, the subsequent tortfeasor is liable for the full extent of the aggravated harm.

Part Three: Special Causation Problems

A. Multiple Defendants and Joint and Several Liability

Causation analysis becomes particularly complex when multiple defendants contribute to a plaintiff’s harm. Pennsylvania and New Jersey have developed different approaches to apportioning liability among multiple tortfeasors, and these differences significantly affect how causation operates in multi-defendant litigation.

1. Pennsylvania: Modified Joint and Several Liability

Pennsylvania has modified the traditional rule of joint and several liability through the Fair Share Act, 42 Pa. C.S. § 7102. Under this statute, a defendant who is found to be less than 60% responsible for the plaintiff’s harm is liable only for their proportionate share of the damages. Only defendants who are 60% or more responsible remain jointly and severally liable for the full amount of damages.³⁹

The Fair Share Act has significant implications for causation proof. Plaintiffs must not only establish that each defendant’s conduct was a cause of the harm, but must also present sufficient evidence to permit the jury to apportion fault among multiple defendants. In cases involving multiple potentially responsible parties—common in construction accidents, multi-vehicle collisions, and toxic tort litigation—careful attention to causation evidence is essential to maximize recovery.

2. New Jersey: Modified Comparative Fault

New Jersey applies the Comparative Negligence Act, N.J.S.A. 2A:15-5.1 et seq., which similarly allocates responsibility among multiple defendants based on their percentage of fault. A defendant is jointly and severally liable only if their fault exceeds 60%; otherwise, the defendant is liable only for their proportionate share.⁴⁰

New Jersey has also adopted the doctrine of successive tortfeasors, recognizing that where a plaintiff suffers an initial injury due to one defendant’s negligence and then suffers aggravated harm due to a second defendant’s negligence (such as medical malpractice in treating the initial injury), both defendants may be liable for the harm each caused.⁴¹

B. Indeterminate Defendant Cases

In some cases, the plaintiff can prove that one of several defendants caused the harm, but cannot identify which defendant was responsible. This problem frequently arises in product liability cases involving fungible products, pharmaceutical litigation, and toxic tort cases involving multiple sources of exposure.

1. Alternative Liability

The doctrine of alternative liability, established in Summers v. Tice (1948) and adopted in the Restatement (Second) of Torts § 433B, addresses situations where two or more defendants acted negligently, the plaintiff was harmed by the conduct of one of them, and the plaintiff cannot prove which defendant caused the harm. In such cases, the burden shifts to each defendant to prove that they did not cause the harm.⁴²

Pennsylvania has recognized alternative liability in appropriate circumstances, though its application has been limited. In Skipworth by Williams v. Lead Indus. Assoc. (1995), the Pennsylvania Superior Court discussed alternative liability in the context of lead paint litigation, noting the doctrine’s requirements and limitations.⁴³

New Jersey has similarly recognized alternative liability but has applied it cautiously. The doctrine requires that all potentially responsible defendants be before the court and that the plaintiff establish that each defendant acted negligently.⁴⁴

C. Medical Malpractice Causation

Medical malpractice cases present distinctive causation challenges. The plaintiff must prove not only that the healthcare provider breached the standard of care, but that the breach caused the plaintiff’s injury—often a difficult task where the plaintiff was already suffering from a disease or condition that may have caused the same outcome regardless of the alleged malpractice.

1. Pennsylvania Standards

In Pennsylvania, the plaintiff in a medical malpractice case must prove, through expert testimony stated with a reasonable degree of medical certainty, that the defendant’s negligence was a substantial factor in bringing about the plaintiff’s harm. In Hamil v. Bashline (1978), the Pennsylvania Supreme Court held that the plaintiff need not prove causation with absolute certainty, but must present evidence from which a jury could reasonably conclude that the defendant’s conduct was a substantial contributing factor.⁴⁸

Pennsylvania applies the substantial factor test with particular rigor in failure-to-diagnose cases. The plaintiff must present expert testimony establishing that earlier diagnosis would have, more likely than not, resulted in a better outcome. Speculation that the outcome might have been different is insufficient.⁴⁹

2. New Jersey Standards and Lost Chance

As discussed above, New Jersey has adopted the lost chance doctrine, permitting recovery even where the plaintiff cannot prove that proper treatment more likely than not would have achieved a better outcome. In Scafidi v. Seiler (1990), the New Jersey Supreme Court held that a patient may recover for lost chance of survival, with damages proportional to the chance that was lost.⁵⁰

The lost chance doctrine significantly affects medical malpractice litigation in New Jersey. A plaintiff whose cancer diagnosis was delayed may recover for the reduction in survival probability, even if the cancer was already more likely than not to be fatal at the time of the misdiagnosis. This approach recognizes that the chance of a better outcome has value and that negligent deprivation of that chance is a compensable injury.

D. Toxic Tort Causation

Toxic tort cases—including asbestos litigation, pharmaceutical injury claims, and environmental contamination cases—present some of the most difficult causation problems in modern tort law. The Philadelphia region, with its industrial history and concentration of pharmaceutical companies, has been a major venue for toxic tort litigation.

1. General and Specific Causation

Toxic tort plaintiffs must establish both general causation and specific causation. General causation asks whether the substance at issue is capable of causing the type of harm alleged—for example, whether asbestos exposure can cause mesothelioma. Specific causation asks whether the substance caused this plaintiff’s harm—whether this plaintiff’s mesothelioma was caused by asbestos exposure rather than some other factor.⁵¹

Pennsylvania courts have required expert testimony on both elements. In Gregg v. V-J Auto Parts Co. (2007), the Pennsylvania Supreme Court addressed the evidentiary requirements for asbestos causation, holding that the plaintiff must present evidence of both exposure to the defendant’s product and a scientifically reliable basis for concluding that the exposure was a substantial factor in causing the disease.⁵²

New Jersey applies similar requirements but has shown some flexibility in recognizing that epidemiological certainty may not always be achievable. In Landrigan v. Celotex Corp. (1992), the Court permitted expert testimony based on reasonable scientific inference where direct proof of specific causation was unavailable.⁵³

2. Frequency, Regularity, and Proximity

In asbestos litigation, Pennsylvania courts have developed the “frequency, regularity, and proximity” standard for proving causation. The plaintiff must present evidence of frequent and regular exposure to the defendant’s asbestos-containing product in proximity to the plaintiff’s work area. This standard, established in Eckenrod v. GAF Corp. (1988), requires more than mere proof of presence at a worksite where asbestos was used; the plaintiff must show meaningful exposure to the specific defendant’s product.⁵⁴

New Jersey has adopted a similar approach, requiring proof of sufficient exposure to the defendant’s product to justify an inference that the exposure was a substantial factor in causing the disease. The mere possibility of exposure is insufficient; the plaintiff must present evidence from which a reasonable jury could conclude that exposure to the defendant’s product contributed to the harm.⁵⁵

Part Four: Practical Considerations for Philadelphia and South Jersey Practice

A. Case Evaluation and Investigation

At the intake stage, counsel must carefully evaluate the strength of the causation evidence. In motor vehicle accident cases arising on I-95, the Schuylkill Expressway, the Blue Route, or the Atlantic City Expressway, causation may be straightforward—the collision caused the plaintiff’s injuries. But in cases involving delayed symptom onset, pre-existing conditions, or multiple potential causes, early attention to causation is essential.

In medical malpractice cases arising at major Philadelphia hospital systems—Penn Medicine, Jefferson Health, Temple Health—or South Jersey facilities in Camden, Cherry Hill, and the surrounding counties, causation analysis must begin with a thorough review of the medical records and consultation with appropriate experts. The choice between Pennsylvania and New Jersey law may be outcome-determinative in lost chance cases.

B. Expert Retention and Preparation

Causation in complex cases depends on expert testimony. Counsel should retain causation experts early and work with them to develop opinions that satisfy the jurisdiction’s evidentiary standards. In Pennsylvania, experts must state opinions with “reasonable degree of medical certainty” or the equivalent scientific formulation. In New Jersey, similar standards apply.

In toxic tort cases, experts must be prepared to address both general and specific causation, to explain the scientific basis for their opinions, and to withstand Daubert-style challenges to the reliability of their methodology. Philadelphia and South Jersey courts have substantial experience with toxic tort litigation and apply rigorous scrutiny to expert causation testimony.

C. Strategic Considerations in Multi-Defendant Cases

Where multiple defendants may have contributed to the plaintiff’s harm, counsel must develop a causation theory that accounts for each defendant’s role while preserving the plaintiff’s ability to recover. Under both Pennsylvania’s and New Jersey’s comparative fault regimes, the jury will apportion responsibility among defendants and the plaintiff. Evidence that clearly links specific harm to specific defendants can maximize recovery by ensuring that responsible parties bear their fair share.

In construction site accidents, automobile collisions involving multiple vehicles, and premises liability cases involving both property owners and contractors, the substantial factor test permits liability to be imposed on multiple defendants whose combined negligence caused an indivisible harm. Counsel should present evidence establishing each defendant’s causal contribution while anticipating apportionment arguments.

Conclusion

Causation is the element that connects the defendant’s wrongful conduct to the plaintiff’s compensable harm. Without proof of causation, a negligence claim fails regardless of how egregious the defendant’s breach or how severe the plaintiff’s injuries. Mastery of causation doctrine—including the but-for test, the substantial factor test, proximate cause analysis, and the special causation problems that arise in toxic tort, medical malpractice, and multi-defendant litigation—is essential to effective personal injury practice.

Pennsylvania and New Jersey share a common doctrinal framework rooted in the Restatement and traditional negligence principles, but meaningful differences exist. New Jersey’s adoption of the lost chance doctrine in medical malpractice cases, the two states’ different approaches to market share liability, and nuances in how courts apply the substantial factor test create a complex landscape for practitioners handling cases in the Philadelphia region and South Jersey.

Counsel should approach every case with careful attention to causation from intake through trial. Early identification of causation issues, thoughtful expert retention, and rigorous development of the evidentiary record are essential to proving that the defendant’s breach—not some other factor—caused the plaintiff’s harm. In a litigation environment where defendants routinely challenge causation through dispositive motions and expert challenges, thorough preparation on this element can make the difference between a successful recovery and a dismissed claim.

About Brian E. Fritz, Esquire

BRIAN E. FRITZ, ESQUIRE has represented seriously injured clients in Pennsylvania and New Jersey for almost 30 years. He has dedicated his practice to providing hope to the victims of others’ negligence and helping them navigate the challenges they now face. His primary focus includes: construction and premises liability; corporate direct liability for negligence; motor vehicle and trucking accidents; dangerous and defective products; unsafe modification of products and machinery; medical malpractice with an emphasis on birth-related injuries and cerebral palsy; exposing liability caused by disguised and hidden corporate decision-makers; establishing vicarious liability where companies have mislabeled workers as independent contractors; securing third-party liability for catastrophically injured workers whose recoveries would otherwise be limited to workers’ compensation; and providing second opinions to seriously injured clients whose cases were initially rejected on mistaken assumptions.

He is admitted to practice law in the State and Federal Courts of Pennsylvania and New Jersey and has handled cases in other jurisdictions on a pro hac vice basis. Based in Philadelphia, he represents clients throughout Pennsylvania and New Jersey. He is a member of the Board of Directors of the Philadelphia Trial Lawyers Association.

He has been recognized annually by his peer attorneys for inclusion in Super Lawyers and has been named one of the Top 100 Attorneys in Philadelphia in the Super Lawyers rankings. He has annually been selected for inclusion in The Best Lawyers in America. His case results have achieved annual national and state recognition by Best of the Bar, reserved for only the top 100 resolutions in any given year. He has annually received Martindale-Hubbell’s AV Preeminent rating for Legal Ability and Ethical Standards based on voting by peer attorneys and members of the Judiciary (Judicial Edition).

Disclaimer: This article is for educational and informational purposes only and does not constitute legal advice. Every case is unique, and the information presented here should not be relied upon as a substitute for consultation with a qualified attorney. If you have been injured, please contact a licensed personal injury attorney in your jurisdiction to discuss the specific facts and circumstances of your situation.