The aim of the study was to use the Repertory Grid technique to explore the construct systems of probation officers, thereby determining what factors were being used in the assessment of offenders. Having elicited this information, the study then attempted to produce and administer a standardized grid to determine the extent to which these criteria were being used to differentiate among treatment options. While there was some degree of commonality in terms of the constructs elicited, recommendations were based almost exclusively on the severity and length of an offender's criminal record. Probation officers were reasonably skilled at differentiating between custody and community service but were less able to differentiate between programs designed for high-risk offenders. Study results suggest that probation officers need some support in assessing offenders and the probation service should adopt a risk assessment instrument to assist in the decision making process. Figures, table, notes, references, appendix