The study used data on felons processed in the district courts over one preguideline (1978) and three postguideline periods (1981, 1982, 1984), and data from a sample of criminal justice officials were used to supplement the quantitative analysis of changes in prosecutorial and sentencing practices over time. The main general conclusion is that the Minnesota guidelines have been effective in increasing the uniformity, neutrality, and proportionality of criminal sanctions, but gains in these areas diminished by 1984. Changes in the policy role of the commission, legislative mandates, and evolving case law which have enhanced the discretionary authority of prosecutors and judges were the major causes of the decline in guidelines effectiveness. Recommendations pertain to how controls can be imposed on prosecutorial discretion within the guidelines themselves, the value of an active policy role by the sentencing commission, the role of appellate review, and how other States can benefit from the Minnesota experience in the construction and implementation of presumptive sentencing standards. For the full report, see NCJ 107743.