Offender Screening Tool (OST)

Author: Maricopa County Adult Probation Department & David J. Simourd, Ph.D.

Purpose: Assess broad based criminal risk/need factors.

Description: The OST is an assessment instrument designed to measure developmental and social factors linked to criminal behavior. It consists of 44 items, 30 or which are dynamic, that are grouped into 10 categories Physical Health/Medical, Vocational/Financial, Education, Family and Social Relationships, Residence and Neighborhood, Alcohol, Drug Abuse, Mental Health, Attitude, and Criminal Behavior. Each item is scored in a binary manner (i.e., “0” – risk factor absent or “1” – risk factor present) with items being summed to yield both category subscores and a total OST risk score. Higher scores indicate greater risk/needs and increased risk for criminality.

Psychometric Information: Normative data exists on the OST among adult probationers among the 14 counties of Arizona. A subset of this data has found the inter-rater reliability of the OST to be r = .97 and the internal consistency (i.e., Cronbach Alpha) estimates for the Total Score being .76. Examination of the predictive validity of the OST found the scores on the instrument correlated (r = .22) with probation outcome in that higher OST scores were related to greater probation difficulties.

Applications: The OST has been used exclusively among probationers in Arizona for case classification purposes.