Reasonableness - Hand Rule

Hand Rule

Under American common law, a well known—though nonbinding—test for determining how a reasonable person might weigh the criteria listed above was set down in United States v. Carroll Towing Co. in 1947 by the Chief Justice of the Second Circuit Court, Learned Hand. The case concerned a barge that had broken her mooring with the dock. Writing for the court, Hand held:

he owner's duty, as in other similar situations, to provide against resulting injuries is a function of three variables: (1) The probability that she will break away; (2) the gravity of the resulting injury, if she does; (3) the burden of adequate precautions.

While the test offered by Hand does not encompass all the criteria available above, juries in a negligence case might well still be instructed to take the other factors into consideration in determining whether the defendant was negligent.