Legal Definitions - abstraction-filtration-comparison test

The Abstraction-Filtration-Comparison Test is a method used by courts in copyright infringement cases to determine if one work has unlawfully copied another. It helps judges decide whether there is "substantial similarity" between two works, meaning that enough of the original, protected expression has been taken to constitute infringement. This test involves three distinct steps:

• Abstraction: In this first step, the court carefully breaks down the original, copyrighted work into its fundamental components, moving from broad concepts to specific details. It dissects the work's structure to identify all the different levels of generality and specificity present.

• Filtration: Next, the court examines each of these components and filters out any elements that are not protected by copyright law. This includes ideas, facts, processes, elements that are common knowledge or in the public domain, or elements where the idea and its expression are so intertwined that there are very few ways to express it (known as "merger material"). What remains after this filtration is the "protectable expression" – the unique creative choices made by the author.

• Comparison: Finally, the court compares the accused infringing work against the core of protectable expression identified in the original work. The goal is to determine if substantial, protected elements of the original work have been copied or misappropriated in the new work.

This test is particularly useful in complex works where separating protectable expression from unprotectable ideas or functional elements is challenging.

Examples:

• Imagine a popular, copyrighted cookbook specializing in unique dessert recipes. A new cookbook is released, and the original author suspects infringement. A court applying the Abstraction-Filtration-Comparison Test would first perform abstraction by breaking down the original cookbook into its elements: the overall theme, chapter organization, specific recipe instructions, unique ingredient combinations, introductory essays, and photographic style. During filtration, the court would remove unprotectable elements such as the general idea of a dessert cookbook, common baking techniques, basic ingredients (flour, sugar), and widely known classic recipes (e.g., a basic chocolate chip cookie recipe). What remains would be the unique, original aspects like a novel ingredient pairing in a specific cake, a distinctive method for decorating, or an original narrative in an introductory chapter. In the comparison phase, the court would then compare these protectable elements with the new cookbook. If the new cookbook features the same novel ingredient pairings, identical distinctive decorating methods, or very similar original narratives, it could be found to have substantially copied the protected expression.

• Consider a copyrighted architectural blueprint for a distinctive, modern public library, celebrated for its innovative use of natural light and a unique, flowing interior layout. When a new community center is built with a strikingly similar design, the library's architect might sue for copyright infringement. The court would begin with abstraction, dissecting the library's design into its structural components: the overall concept, specific geometric forms, the unique skylight design, the arrangement of reading nooks, and the flow between different functional zones. During filtration, the court would remove unprotectable elements, such as the general idea of a public library, standard building materials (concrete, glass), common structural engineering principles, or functional elements dictated by building codes (e.g., fire exits). The remaining protectable expression would include the unique combination of geometric shapes, the specific and novel design of the skylight, or the original aesthetic choices in the interior layout that go beyond mere functionality. Finally, in the comparison step, the court would assess whether the community center's design incorporates these specific, protectable elements from the library's blueprint, thereby determining if substantial similarity exists.