On March 10, 2015, a jury determined that performers Robin Thicke and Pharrell Williams copied Marvin Gaye’s 1977 song Got to Give It Up when the duo created the 2013 hit song Blurred Lines. The jury found Thicke and Williams liable for copyright infringement and awarded $7.4 million dollar to the children of Gaye.

Although most individuals will compare the two audio recordings and/or listen to a “mashup” of the two songs on YouTube before reaching a conclusion, the legal analysis is not so simple. From an intellectual property law standpoint, this case is particularly interesting.

Gaye recorded Got to Give It Up in December 1976. At that time, the Copyright Act of 1976 had been signed into law two months earlier, but did not go into effect until January 1, 1978. As a result, aspects related to the copyright(s) of Got to Give It Up were governed by the Copyright Act of 1909.

As noted by the judge in a ruling for summary judgment, “in order to claim copyright in a musical work under the 1909 Act, the work had to be reduced to sheet music or other manuscript forum.” The Copyright Act of 1976 broadened the scope of federal copyright protection to include “works of authorship fixed in any tangible medium of expression,” thereby encompassing a sound recording of a composition.

Due to the timing of Gaye’s recording relative to the effective date of the Copyright Act of 1976, his copyrights were limited to the sheet music compositions. In fact, the federal district judge granted Thicke and Williams a motion in limine to prevent the full, produced audio recording of Got to Give It Up from being played at the trial; a redacted version consistent with the sheet music was played for the jury.

To succeed at trial, lawyers for the Gayes were tasked with proving that the lyrics, melody and chords contained in the sheet music were copied when composing Blurred Lines. The sheet music of Got to Give It Up, however, was reportedly missing several elements commonly associated with the produced audio recording, such as, most notably, the well-known drum beat.

The legal test for copyright infringement is a two-part analysis, each of which addresses whether the allegedly infringing work is “substantially similar” to the copyrighted work. Despite the similar verbiage, the analyses are separate and distinct. The first inquiry is considered to be a lower threshold and involves: (i) showing the alleged infringer had access to the copyrighted work; and (ii) the two works are substantially similar such that the alleged infringing work was copied from the copyrighted work. In the case of Thicke and Williams, the popularity and distribution of Got to Give It Up no doubt proves access, and Thicke cited the song as inspiration when composing Blurred Lines. If the first inquiry is answered in the affirmative, the jury determines whether the alleged infringer copied a substantial amount of protectable expression. Whether Blurred Lines was substantially similar to the protectable expression captured in the sheet music of Got to Give It Up such that it misappropriates the same is certainly a question reasonable minds differ.

The verdict has had some divisive fallout. Many artists applaud the verdict for advancing strong copyright protection. Others believe the facts of the case create blurred lines in copyright law, from which the resulting unpredictability may stifle creativity when artists look to features of existing works for inspiration.