In July 1980, the State Bar of California conducted an experiment with 485 bar applicants who volunteered to participate in performance tests in addition to taking the regular bar exam. To give applicants an incentive to participate, the experimental performance tests could only increase but not decrease their chances of passing the bar exam. The experiment was led by UCLA School of Law professor Paul Bergman and RAND Corporation psychometrician Stephen P. Klein. Based on their results, the State Bar added a three-hour-long performance test to the July 1983 bar exam administration. California performance tests are usually situated in the fictional state of Columbia.