the appropriateness of deterrence and incapacitation strategies as means for reducing violent offending.

Throughout the analysis, we limit consideration to incarceration in state prisons—the primary site for long-term institutionalization of violent offenders—and exclude local prisons and jails. When referring to violent offenses, we include murder (which usually includes nonnegligent homicide), aggravated assault, rape, and robbery. For purposes of comparison, we also analyze burglary and drug offenses, two nonviolent offenses that figure prominently in prison populations.¹ We rely primarily on annual data from 1965 to 1988 for selected states. State-level data are especially useful because they provide annual counts of both admissions to prison and resident populations disaggregated by crime type.

The analyses of prison populations are designed to answer three main questions:

1. What is the contribution of incarceration for violent crimes to the changes over time in the total prison population?

2. How have sanction policies regarding the certainty and severity of imprisonment for violent crimes changed over time?

3. What is the contribution of changing sanction policies for violent crimes to changes in the size of the prison population?

With regard to the crime control effects of incarceration, we are especially concerned with examining whether incarceration is an effective strategy for controlling violent crimes and the merits of pursuing alternative incarceration policies.

In addition to national data, we obtained corrections data from the following states: California, Florida, Michigan, New York, Pennsylvania, and Texas.² These states were selected because they are geographically distributed in various regions of the United States, and together they comprised 38.5 percent of total prisoners under jurisdiction in state and federal institutions in 1988 (Bureau of Justice Statistics, 1990a). All of the states provided annual data on commitments to prison and average daily population (typically a one-day census of the resident inmate population) disaggregated by crime type and for the total over all crime types.³

The data for each state vary somewhat in the years covered. New York and California are the most complete, and cover the entire period from 1965 to 1988; the data for the remaining states