The JI–R normative sample included 4,380 individuals from across North America — 3,421 were nondelinquent and 959 were delinquent.
Almost all studies using the JI–R have verified its ability to distinguish delinquents from nondelinquents. Many have demonstrated its predictive validity as well. Odd-even item correlations and Cronbach's alpha are presented to demonstrate the consistency in JI–R items. Test-retest reliability is presented to indicate the temporal stability of JI–R ratings. Further information pertinent to JI–R validation is available in the technical manual.
For more information on the JI–R click here.
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Dr. Carl Jesness
Carl Jesness received his Ph.D. from the University of Minnesota in 1955. Following two years of post-doctoral training, he was employed as a clinical psychologist with the Veteran's Administration and the California Youth Authority. In 1959, he began his long career as a researcher in the field of juvenile delinquency as a senior research analyst for the Youth Authority to head the Fricot Ranch Study. The study was the first of many research projects he supervised over the next 26 years, initially as a behavioral scientist, and later as chief of the Research Bureau. During the course of these projects, he recognized that it was essential to evaluate any program-related changes in the attitudes and behavior of the youth involved in California Youth Authority programs, but found that valid measures for these purposes did not exist. As a result, Dr. Jesness embarked on an effort to develop appropriate and valid psychological instruments that were to continue even past his retirement from the Youth Authority in 1985.
Although most of his publications have described the results of his many research projects, Dr. Jesness is most widely known as the author of the measure that resulted from these efforts - Jesness Inventory™, Jesness Inventory Classification System™, and Jesness Behavior Checklist™.
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