An Analysis of Intra-individual Variability in Criminal Propensity

Understanding criminal propensity requires reconciling two apparently contradictory dynamic patterns observed across studies. There is a general trend for criminal behavior to remain stable over time, and a general trend for it to fluctuate. The first pattern suggests that behavior is related to stable traits of the individual, while the second suggests it is related to transient states. Long term studies indicate that rank order differences in criminal propensity are fairly stable over the life course — consistent with a trait that shows stable rank order consistency between individuals with a gradual mean level decline over the adult life course. Short term studies indicate substantial fluctuation in criminal propensity with changes in local life circumstances such as employment, relationship stability, and drug use — consistent with a state description. This study examines the connection between trait and state aspects of criminal propensity using 57,473 criminal offenders placed on probation in England from 2005 to 2006. Results indicate that the size of intra-individual fluctuations in criminal propensity is related to the likelihood that trait levels of criminal propensity will decline over time. Smaller state fluctuations — that is, higher consistency between measurements — are associated with a greater likelihood of declining trait level propensity, suggesting that stability of state may be a mechanism for trait level change. Several aspects of this phenomenon are analyzed in the context of dynamic risk assessment and life course criminology. Criminal propensity data were collected using the Offender Assessment System (OASys; Howard, Clark, Ministry of Justice, 2009), the standard risk assessment instrument used in England and Wales.