The U.S. Parole Commission's procedures have evolved over the years from a system which made parole decisions on a case-by-case basis with essentially no structure, through a period where structure was developed for paroling decisions through policy guidelines, to the current system which combines the use of guidelines with the setting of presumptive dates. The development of guidelines based on preincarceration factors permitted the development of the presumptive date procedures. Presumptive date procedures, in turn, required a restructuring of the process used to consider institutional and other postincarceration factors in the release decision. Although the current Federal parole procedures have developed in piecemeal fashion, what has emerged is a conceptually simple system which provides for the early setting of a tentative data for parole based on factors known at the time of commitment (offense severity and risk assessment), with provision for the modification of that release date based on factors of significance which become known during confinement, e.g., retardation for disciplinary infractions and advancement for exceptionally positive accomplishments. Further, the system is designed to contain sufficient structure to provide consistent decisionmaking for similarly situated offenders while being flexible enough to accommodate significant differences among offenders. Appended are the guidelines for parole decisionmaking, including factors that can extend or shorten the parole decision date. A total of 18 footnotes are listed. (Author summary modified)