The diagnostic category of sociopathic personality in early editions of the Diagnostic and Statistical Manual (DSM)[205] had some key similarities to Cleckley's ideas, though in 1980 when renamed Antisocial Personality Disorder some of the underlying personality assumptions were removed.[2] In 1980, Canadian psychologist Robert D. Hare introduced an alternative measure, the "Psychopathy Checklist" (PCL) based largely on Cleckley's criteria, which was revised in 1991 (PCL-R),[167][206] and is the most widely used measure of psychopathy.[207] There are also several self-report tests, with the Psychopathic Personality Inventory (PPI) used more often among these in contemporary adult research.[6]