Computer Associates and Altai both developed job scheduling software, and Computer Associates accused Altai of copyright infringement. In determining whether copyright infringement existed, the Court took this opportunity to introduce a test, the Abstraction-Filtration-Comparison (AFC) test. The AFC test begins by breaking down the copyrighted software into its structural parts ("abstraction"). The portions in the public domain, incorporated ideas, and expression necessary to those ideas are filtered out ("filtration"). Finally, the court compares the residue of remaining creative expression to see if the protected elements are substantially similar to the allegedly infringing software ("comparison").

Determine the different levels of abstraction inherent in the work. Descend from high level conception to granular functionality. Purpose of program, to program modules that fulfill that purpose, to subroutines that support those modules, to the source code.

Filter out elements dictated by external considerations, such as efficiency and compatibility.

The Court applied its new AFC text to the two programs and held that the non-literal elements of Altai's program were not substantially similar to the program copyrighted by Computer Associates. Infringement was not found.