While fair use remains ambiguous and the four-part test can seem esoteric, it has served the US well for decades.

The Court also rejected the four-part test applied in Dendrite International, Inc. v. Doe No. 3.

In its unanimous ruling, the court borrowed from a 1995 decision in Wisconsin that established a four-part test to determine whether someone had attained the status of a functional or psychological parent.

Section 1-201 of the Uniform Commercial Code defines a "Buyer in the ordinary course of business" by a four-part test:

In 1962, the board adopted a four-part test in Hollywood Ceramics Co. to determine what constituted an egregious fabrication.

Injunctions are currently awarded in patent infringement cases if the plaintiff satisfies a four-part test.

There is a standardized four-part test for determining if an asset is appropriate for reserve designation:

Fair use can extend beyond these listed purposes (note the "such as" statement in the law), but to qualify as "fair," a use has to pass the famous four-part test, which considers the following factors:

Questions on the three-hour, four-part test are drawn from high school curriculums, not general knowledge, designed to test how much students have learned rather than how smart they are.

In this case, the Court held that the four-part test outlined in Turner v. Safley was met.