In order to bring a copyright infringement lawsuit, the copyright holder must be able to establish three elements. The first, ownership of a valid copyright, requires that the copyright relate to an original work of authorship that is fixed in a tangible medium. The second element requires actual copying of that work, which can be shown using either direct evidence, indirect evidence, or a combination of both. Finally, a copyright holder must prove misappropriation. It is this third element that goes directly to the question posed in this article. How much of my work can be incorporated in another work before it constitutes copyright infringement?

Unfortunately, there is no definitive answer to this question. Instead, one must look to case law precedent to establish how much is too much. That being said, when alleging copyright infringement, the copyright holder must show that what was indeed taken and incorporated into the allegedly infringing work was copyright protectable. Once this is established, it is up to the plaintiff to show that the audience for the work will recognize "substantial similarities" between the two works. Although there is no set percentage, for example, to determine whether substantial similarity exists, two commonly recognized methods are available to assist in the misappropriation portion of a copyright infringement analysis.

The first method, known as the subtractive method or the abstraction/subtraction approach, first identifies what parts of the work are protectable. The method then directs the finder of fact to eliminate, or subtract, those elements that are not protectable. The remaining elements are then compared to the allegedly infringing work to determine whether substantial similarities exist.

The second method, known as the totality method or total concept and feel approach, leaves the works in their entirety when doing the analysis. In particular, the entire copyrighted work is pitted against the allegedly infringing work to determine whether a substantial similarity exist. Clearly, it is the goal of the defendant to show differences between the two works in an effort to avoid liability.

Today, courts will employ each of the above methods, and at times both methods, to aid in the misappropriation analysis. Given the factual nature of copyright law, it is not out of the question for one method to favor a copyright holder while the other method favors the alleged infringer. Therefore, it is worthwhile to, at the outset of any intended action for copyright infringement, analyze the likelihood of success under both methods. This will not only enable the copyright holder to identify the strengths and weaknesses of the particular case, but it will also allow the copyright holder to make a decision whether or not it is worthwhile pursuing a copyright infringement lawsuit. In the alternative, cease and desist letters, negotiation, for an amicable resolution, or other means short of litigation, such as copyright licensing, may be a possibility worth exploring.

Therefore, while ownership of a valid copyright and actual copying are two factors that also require particular analysis, oftentimes the misappropriation element is the determinative factor in a copyright infringement matter. Copyright holders are well-served to fully analyze the extent of misappropriation just as defendants to a copyright infringement lawsuit should constantly be looking to identify elements that negate a finding of substantial similarity.