In recent months the board has overturned patents on a computer memory technology, a popular videogame, and a system for monitoring car tires. The PTAB has invalidated at least one “claim”—or part—in almost 80% of the patents it has ruled on, according to a study in the University of Chicago Law Review. Some patent experts such as Randall Rader, former chief judge at the U.S. Court of Appeals for the Federal Circuit, have referred to the 300-odd administrative judges, attorneys and legal aids on the board as “patent death squads.”