In response to these problems, our recent efforts have been directed toward the development of a behavioral checklist for psychopathy. The psychometric qualities of the checklist were evaluated using generalizability theory and classical test score indices of reliability. In each of 5 years two raters (usually different each year) rated a number of prison inmates (total N=301) on 22 items. The generalizability coefficients were .85, .86, .90, .86, and .89, for the years 1977 to 1981, respectively. The generalizability coefficient for a test-retest study was .89. Classical indices of reliability (alpha coefficients, inter- and intrarater reliability) ranged from .82 to .93. The results indicate that the checklist is a very reliable (generalizable) instrument when used with prison populations. It is highly correlated with global ratings of psychopathy and criteria from the Diagnostic and Statistical Manual of Mental Disorders (3rd ed.) for Antisocial Personality Disorder. (Publisher abstract)