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Measure of Skewness in Offense Distributions

NCJ Number
114909
Journal
Journal of Quantitative Criminology Volume: 4 Issue: 3 Dated: (September 1988) Pages: 259-274
Author(s)
J A Fox; P E Tracy
Date Published
1988
Length
16 pages
Annotation
It has become a criminological truism that a small group of offenders is responsible for a far greater proportion of offending than its size would suggest.
Abstract
For example, in the 1945 Philadelphia birth cohort, 6 percent of the cohort members committed 52 percent of the offenses. In this paper, it is argued that the conventional percentage approach to measuring skewness in offense distribution is inadequate. An alternative approach to measuring offense skewness is proposed and applied. This approach, taken directly from a similar concept of income distribution in economics, is invariant across cohorts. Thus, regardless of the size of the cohorts studied or differences in the concentration of delinquents or the total number of offenses they have committed, the index can be used to compare the offense distributions observed. This index also uses offense distribution information to its fullest, rather than using some arbitrary cut-off point. By producing information that is comparable across various research designs and methods, the index can contribute to the knowledge of career criminals and criminal careers. 2 tables, 5 figures, and 13 references. (Author abstract modified)