In 1993, the New Hampshire Division for Children, Youth, and Families introduced an objective guidelines instrument to help determine eligibility for placement at the State's juvenile training school. The instrument was intended to improve the consistency of dispositions and narrow training school placements to serious and/or chronic offenders by focusing recommendations on youths' offense characteristics and placing limits on the discretion of probation officers and judges. An evaluation of the implementation and impact of the guidelines analyzed 1 year's use of the instrument and surveyed probation officers' and judges' attitudes toward and experiences with the guidelines. The results show that the guidelines did not have their intended impact, because they were not faithfully and consistently implemented. The officials and staff charged with using them resisted the limits the guidelines attempted to place on their discretion. Guidelines must provide for some discretion, but the range of discretion should be controlled. In the New Hampshire guidelines, discretion remained in the allowances for aggravating and mitigating factors, along with the possibility of overrides; however, overrides were not subject to administrative review and became so frequent that the potential effect of the guidelines was undermined. This article concludes with a listing of what is required for the successful development and implementation of juvenile dispositional guidelines. 2 figures, 6 tables, and a 41- item bibliography