The Suicide Concerns for Offenders in Prison Environment (SCOPE) screening instrument addresses some of the gaps apparent in the literature. Further research with SCOPE would seek to evaluate the predictive validity of the instrument in relation to the identification of individuals at risk of suicidal or nonfatal self-harm behavior. With the majority of suicides occurring within the first 72 hours after entry to a prison or jail, identification of possible immediate risk must be conducted on intake to an establishment. This study aimed to develop an instrument to assess vulnerability to risk of suicide and self-harm behavior that was specifically designed for males and females. The study investigated the item development, factor structure, and validation of the newly devised SCOPE screening instrument. Three studies were conducted to assess the psychometric properties of the new instrument using both exploratory and confirmatory factor analysis in different samples. Participants in all 3 studies consisted of 1,166 young adult offenders across the 6 Her Majesty's Prisons. Figure, tables, appendix, and references