LA Copyright Society

Upcoming Events:

September 23, 2026 at 6:30 p.m. PT

Crustacean Beverly Hills

Has the Hamburglar Finally Come for Krofft?

Substantial Similarity in the Ninth Circuit

with Profs. David Nimmer and Xiyin Tang

Nearly half a century ago, the Ninth Circuit handed down Sid & Marty Krofft Television Productions, Inc. v. McDonald’s Corp., the landmark copyright case arising from the uncanny resemblance between the fantastical worlds of H.R. Pufnstuf and McDonaldland.

Krofft gave the Ninth Circuit copyright law one of its most enduring—and most confounding—doctrines: the two-part extrinsic/intrinsic test for substantial similarity. The framework has evolved considerably since 1977, but it remains the governing test today.

Critics have questioned the test almost from the beginning. What exactly belongs in the “extrinsic” analysis? What does “total concept and feel” mean in an “intrinsic” inquiry? When may courts dissect works into protectable and unprotectable elements—and when must they resist doing precisely that? And how much of Krofft itself remains good law after decades of doctrinal renovation?

Join the Los Angeles Copyright Society for a timely discussion of substantial similarity in the Ninth Circuit: where the doctrine came from, what the courts have made of it, and whether Krofft—and the framework it spawned—is finally approaching its judicial comeuppance.

Professor David Nimmer is Of Counsel to Irell & Manella and teaches copyright law at UCLA School of Law. Widely recognized as a foremost expert in copyright law, David Nimmer represents clients in the entertainment, publishing and high technology fields. He has twice served as co-counsel representing clients before the U.S. Supreme Court. On the first occasion, a unanimous decision in favor of his client drew the boundaries between copyright and trademark protection. In the second, another unanimous decision in favor of his client set the stage to compensate all freelance journalists in the country for their past articles.

David gave congressional testimony at the invitation of the House Judiciary Committee in 2014, on behalf of the United States Telephone Association in 1997 and on behalf of the National Association of Broadcasters in 1992. He also delivered Parliamentary testimony on behalf of the Combined Newspaper and Magazine Copyright Committee of Australia in Sydney.

Since 1985, David has authored and updated Nimmer on Copyright, the standard reference treatise in the field, first published in 1963 by his late father, Professor Melville B. Nimmer. The U.S. Supreme Court has cited Nimmer on Copyright on numerous occasions, as has every federal appellate court, countless district and state courts, as well as courts confronting copyright cases in countries across the globe. Cases within the United States have relied on Nimmer on Copyright as authority in over 3,500 judicial opinions.

Xiyin Tang is a Professor of Law at UCLA School of Law. She has previously served as the Herman Phleger Visiting Professor of Law at Stanford Law School, a lead counsel for Facebook, and an associate at Mayer Brown and Skadden Arps Slate Meagher & Flom LLP, where she worked on a variety of transactional and litigation matters in the technology, media, and entertainment sectors. Tang’s research focuses on the roles that technological evolution and new modes of dissemination play in the law of intellectual property. Her publications have appeared in the NYU Law Review, Columbia Law Review, Michigan Law Review, and Yale Law Journal, among others. Tang received her B.A. from Columbia University and a J.D. from Yale Law School, where she served as Editor-in-Chief of the Yale Journal of Law and Technology.