Finally, the Rehabilitation Unit was replaced in January 1974 with the Rehabilitation Project Force, or RPF. According to Hubbard, "the RPF has been created by the Commodore so that redemption can occur. That is basically its only purpose." He identified four categories of people who were to be assigned to the RPF: "rockslammers" (people deemed to have hidden evil intentions, as detected by the E-meter); people who were unproductive and scored poorly on the Oxford Capacity Analysis personality test; "repeated stat crashers", people who were held responsible for declines in Scientology organizations' productivity; and "overt product makers", people who produced poor-quality work. As before, the unit was to work on "one job, one place, one time." A five-hour study period was to be implemented each day to improve the individuals' knowledge of Scientology. According to David G. Bromley and Douglas E. Cowan, the RPF involves a daily regimen of five hours of auditing or studying, eight hours of work, often physical labor, such as building renovation, and at least seven hours of sleep.