## Introduction

Breach of duty is a core part of negligence in US tort law. It occurs when someone fails to use the level of care the law requires under the circumstances, and that shortfall directly and substantially contributes to another person’s injury. To win a negligence claim, plaintiffs generally must prove four elements: duty, breach, causation, and damages. This guide focuses on breach—how courts decide what the standard of care is, how foreseeability factors in, and what evidence moves the needle in real cases.

We’ll use plain examples like medical malpractice and slip-and-fall claims, highlight leading cases such as Palsgraf, and close with a checklist and quick reference you can use in practice or study.

## What You’ll Learn

- What “breach of duty” means and how it fits within negligence
- How courts determine the standard of care in everyday and professional settings
- The role of foreseeability and the scope of risk in evaluating breach
- How breach connects to causation and damages
- Practical examples: medical malpractice and slip-and-fall
- Key cases: Palsgraf v. Long Island R.R. and Donoghue v. Stevenson
- Common defenses (comparative negligence, assumption of risk) and how they work
- Practical steps for gathering evidence and using experts
- Quick pointers on related topics like negligence per se and respondeat superior

## Core Concepts

### What Is a Breach of Duty?

- Definition: A breach of duty is conduct that falls below the legally required standard of care owed to another person, which then directly and substantially contributes to that person’s injury.
- Where duty comes from: Duties arise from common law (judge-made rules), statutes and regulations (safety codes, traffic laws), contracts, and special relationships (doctor-patient, property owner-visitor).
- Conduct vs. omissions: Breach can be an action (e.g., prescribing the wrong medication) or a failure to act when the law requires action (e.g., not repairing a known hazard). Generally, people don’t have a duty to rescue strangers, but there are important exceptions (special relationships or when a defendant created the risk).
- Reasonableness: Courts ask whether a reasonably careful person (or professional) would have acted the same way under similar circumstances.

### Standard of Care Across Contexts

- Everyday negligence: The “reasonable person” standard applies. Jurors consider what risks were foreseeable and how much effort it would have taken to reduce or avoid the harm.
- Professional negligence (medical malpractice and other licensed fields):
  - Professionals must use the skill and care that a reasonably prudent professional would use under similar circumstances.
  - Most states require expert testimony to define this standard and explain how the defendant fell short.
- Premises liability:
  - Property owners generally must keep their premises reasonably safe and warn of non-obvious hazards.
  - Many states still refer to visitor categories (invitee, licensee, trespasser), while others apply a unified reasonableness approach.
  - For slip-and-fall claims, plaintiffs usually must show the owner created the hazard or had actual or constructive notice of it and failed to correct it.
- Statutory standards (negligence per se):
  - Violating a safety statute or regulation designed to protect the injured person from the type of harm suffered can establish breach, if the statute applies and the violation caused the harm.

### Foreseeability and Scope of Risk

- Foreseeability guides what risks a reasonable person would guard against.
- Courts look at the scope of the risk: Was the type of harm that occurred among the risks that made the conduct dangerous in the first place?
- Palsgraf teaches that a defendant’s responsibility is limited to harms within the zone of foreseeable danger. Random, highly attenuated harms usually fall outside that zone.

### Causation Link and Damages Overview

- Actual cause: The injury would not have happened “but for” the defendant’s conduct (or the conduct was a substantial factor in causing it).
- Proximate cause: Limits liability to harms that were a reasonably foreseeable result of the conduct.
- Damages: Plaintiffs must show losses caused by the breach, such as medical bills, lost wages, and pain and suffering. Loss of earning capacity is available in many cases if proven with evidence.

### Common Defenses You’ll See

- Comparative negligence: The plaintiff’s own negligence reduces recovery by their percentage of fault. Some states bar recovery if the plaintiff is 50% or 51% at fault; others allow partial recovery regardless of percentage.
- Contributory negligence (minority rule): Any plaintiff fault bars recovery entirely (used in a few jurisdictions).
- Assumption of risk: Express waivers or implied conduct showing the plaintiff knowingly accepted a specific risk may limit or bar claims, subject to state law and public policy limits (e.g., many states do not allow waivers of gross negligence).
- Superseding cause: An unforeseeable, intervening event that breaks the causal chain can defeat liability.
- Immunities and protections: Government entities may have statutory immunities; Good Samaritan laws can protect certain rescuers; recreational-use statutes can limit landowner duties to recreational users.

## Key Examples or Case Studies

- Medical malpractice example:
  - A physician prescribes a drug that is contraindicated for the patient’s condition without checking the chart. The patient suffers preventable complications. With expert testimony showing the accepted practice and how the doctor fell short, a jury could find breach of duty.
- Slip-and-fall example:
  - A supermarket leaves melted ice creating a puddle in a high-traffic aisle for an extended period without warning signs. A shopper slips and fractures a wrist. If records and video show the condition existed long enough that the store should have discovered and fixed it, a jury could find breach.

- Palsgraf v. Long Island R.R. Co. (N.Y. 1928):
  - Facts: Railroad guards helped a passenger board a moving train; a package fell and exploded, causing scales to strike Ms. Palsgraf on a distant platform.
  - Takeaway: The court denied recovery, reasoning Ms. Palsgraf’s injury was outside the foreseeable zone of risk created by the guards’ conduct. Foreseeability helps set the limits of duty and proximate cause.
- Donoghue v. Stevenson (UK 1932):
  - Facts: A consumer became ill after drinking a ginger beer that allegedly contained a decomposed snail.
  - Takeaway: Often cited for modern duty concepts, the case explains that manufacturers owe reasonable care to those foreseeably affected by their products. In negligence cases involving products, failing to use reasonable manufacturing and quality controls can amount to breach.

## Practical Applications

Building a plaintiff’s case on breach:

- Identify the duty: Is it based on common law, a statute, a regulation, a contract, or a professional obligation?
- Pin down the standard: Use industry guidelines, written policies, training materials, accreditation standards, and, for professionals, expert testimony.
- Prove notice and foreseeability: Show prior incidents, complaints, inspection logs, or maintenance gaps to establish the defendant knew or should have known about the risk.
- Show safer alternatives: Demonstrate feasible precautions (signage, guardrails, checklists, staffing, monitoring) the defendant could have used with modest cost or effort.
- Preserve and present evidence: Photos, videos, incident reports, electronic logs, black-box data, medical records, and witnesses. Move quickly to avoid spoliation issues.

Defending a breach claim:

- Document reasonable care: Show the policies, training, and inspections actually used in practice, not just on paper.
- Challenge notice and causation: Argue the hazard was sudden and not reasonably discoverable, or that another cause explains the injury.
- Use defenses strategically: Comparative negligence, assumption of risk, contractual waivers (when permitted), and superseding cause can reduce or defeat recovery.
- Experts matter: Engage qualified experts early to define the standard of care and rebut the plaintiff’s theory.

Context-specific tips:

- Medical malpractice:
  - Secure all records early; identify the proper defendants, including institutions; confirm pre-suit requirements in your state (certificates of merit, notices).
- Premises liability:
  - Audit cleaning and inspection logs; verify camera retention policies; confirm employee training on hazard recognition and response.
- Employer liability (respondeat superior):
  - An employer can be liable for an employee’s breach committed within the scope of employment; examine job duties, timing, and location of the act.
- Statutes of limitations:
  - Filing deadlines vary by state and case type. Some claims have pre-suit notice rules (e.g., claims against government entities). Calendar them early.

Related topics to review:

- Respondeat superior (employer liability for employee negligence)
- Loss of earning capacity (damages)
- Waiver as a defense (assumption of risk)
- Slip-and-fall claims (premises liability)
- Toxic torts (exposure, causation, and foreseeability)

## Summary Checklist

- Confirm the four negligence elements: duty, breach, causation (actual and proximate), and damages.
- Define the standard of care for the situation (reasonable person or professional standard).
- Assess foreseeability and the scope of risk presented by the conduct.
- For premises cases, evaluate creation of the hazard, actual or constructive notice, and reasonable inspection practices.
- For professional cases, line up qualified experts and accepted practice guidelines.
- Consider negligence per se if a safety statute or regulation was violated.
- Assemble evidence: records, logs, policies, video, photos, physical evidence, and witness statements.
- Address defenses early: comparative or contributory negligence, assumption of risk, superseding cause, immunities, and waivers (as permitted by state law).
- Tie breach to specific harms and quantify damages, including medical costs, lost income, and pain and suffering.
- Track all deadlines, including pre-suit notices and statutes of limitations.

## Quick Reference

| Concept                | Authority/Source                | Key Takeaway                                                |
| ---------------------- | ------------------------------- | ----------------------------------------------------------- |
| Breach of duty         | Restatement (Third) of Torts §3 | Conduct falls below reasonable care given foreseeable risks |
| Foreseeability limits  | Palsgraf v. Long Island R.R.    | Liability limited to harms within the zone of risk          |
| Negligence per se      | State safety statutes           | Statute violation can establish breach and causation        |
| Medical malpractice    | State malpractice statutes      | Professional standard proven by expert testimony            |
| Comparative negligence | State comparative fault laws    | Plaintiff’s fault reduces recovery by percentage of fault   |

Breach of Duty in Negligence: Definition, Standards, and US Case Law