These coalitions found various ways to introduce determinacy into the sentencing decision. Determinacy could come in the form of (1) a sentencing schedule prescribed by the legislature or by a sentencing commission or (2) in parole guidelines limiting the discretion of parole boards. The shift from indeterminacy to determinacy also represented a shift from dealing with sentences on an individual basis to dealing with them in aggregate terms. Legislature and sentencing commissions generally found 'just deserts' with its fundamental demand for 'proportionality' to be an appropriate philosophy. The vigor with which sentencing policy has been reconsidered has stimulated greater attention to the two fundamental purposes served in sentencing: retribution and crime control. In recent years, a number of excellent examples have emerged of the use of prison impact estimation as an explicit consideration in the development of sentencing policy. One is the Minnesota Sentencing Guidelines Commission, which used available prison capacity as a constraint on the sentencing schedule it developed. Another is Pennsylvania's use of prison impact analysis in the development of a mandatory-minimum sentencing law. These two cases illustrate the technical feasibility of developing reasonable estimates of the impact of sentencing policy on prison populations and the political feasibility of making use of those estimates in the development and acceptance of responsible sentencing policy. A total of 23 footnotes are included.