§ 4.01  Overview [67-68]

 

Breach of duty is the defendant's failure to act as a reasonable person would have under the same or similar circumstances.  More simply, breach is unreasonable conduct by the defendant. Where reasonable minds can disagree, the jury is charged with the task of deciding whether the defendant has breached a duty.

 

§ 4.02  The Risk Calculus [68-74]

 

Negligence liability is imposed where the defendant engages in unreasonable risk creation, situations where the defendant creates risks that a reasonable person would not. This determination of unreasonableness considers the risks that should have been foreseen at the time of the defendant's conduct, not through hindsight after the harm occurred. Justifications for placing legal responsibility only on those at fault include promoting freedom of activity, maximization of innovation and economic efficiency.  How is unreasonableness determined?  Many adhere to Judge Learned Hand's risk calculus [see § 17.01[B][1], infra] looking at whether the burden of avoiding the harm is less than the probability of that harm occurring multiplied by the likely seriousness of the harm if it does occur.  The Hand formula was intended to be flexible. The plaintiff and the defendant often will have different views of probability, magnitude, and burden. It is ultimately for the trier of fact to undertake the balancing of these factors in order to assess the reasonableness of the defendant's conduct.

 

            [A] Probability

 

The probability factor seeks to measure the likelihood of the harm-causing occurrence taking place. Although probability must be considered in relation to magnitude and burden, where there is a minuscule likelihood of harm it is doubtful that the defendant breached a duty.

 

            [B] Magnitude of the Loss

 

The magnitude of the loss looks at the likely harm flowing from the injury-causing event when it occurs. The proper focus is neither the most severe possible harm nor the least severe; rather, it is what a reasonable person would foresee as the likely harm.

           

            [C] Burden of Avoidance

 

An analysis of burden requires consideration of such things as the costs associated with avoiding the harm, alternatives and their feasibility, the inconvenience to those involved and the extent to which society values the relevant activity. 

 

            [D] Value of the Hand Formula

 

While the jury is not instructed to consider the Hand formula factors, they reflect the kinds of things that a jury grapples with in determining reasonableness. In addition, the attorneys when arguing the case to the jury surely raise points, such as the ease of avoiding the harm, that fit into a Hand-type analysis. Further, the Hand factors often are expressly used by judges reviewing jury verdicts.  Judge Hand did not intend that the formula be quantifiable.  Rather, it was to serve as a rough guide in the determination of unreasonableness.

 

§ 4.03  The Role of Custom [74-76]

 

Custom typically refers to a well-defined and consistent way of performing a certain activity, often among a particular trade or industry. The plaintiff may try to assert the defendant's deviation from custom as evidence of lack of due care. Conversely, the defendant may try to avoid liability by showing compliance with custom.

 

            [A] Deviation from Custom

 

If P can persuade the jury that there is a well-established and relevant custom, the jury may consider D's deviation from custom in its determination of breach of duty. Evidence of D's deviation from custom is often powerful evidence of breach although it does not itself establish the defendant's unreasonableness.  Nor does the introduction of custom evidence change the standard of care in most negligence cases. 

           

            [B] Compliance with Custom

 

Evidence of D's compliance with custom is usually admissible as evidence of D's lack of breach. Evidence of D's compliance with customary practice does not alter the standard of care nor does it conclusively establish D's lack of unreasonableness.  A jury is free to determine that the custom itself is an unreasonable one.

 

§ 4.04  The Jury Role [76-78]

 

Where reasonable minds could disagree, the jury decides whether the defendant acted unreasonably. The notion (once favored by Justice Holmes) that courts should create standards of conduct to be used in similar cases has largely been repudiated.