The nation's prison population has reached a new equilibrium between crime and its responses to crime. The rate of incarceration per 100,000 U.S. residents increased between 1980 and 2000, but has remained relatively stable since then. In recent years, incarceration rates have gone slightly downward, and crime rates reached the lowest they have been since the 1960s (see Figure 1). If leadership doesn't address prosecution, sentencing and release policies, prison populations will not decline further, and more importantly, if crime goes up again, prison populations will rise.
Sources of prison growth
Understanding past sources of growth can provide indications on how the U.S. may reduce the rate of incarceration. Nationally, and according to an analysis conducted by Allen Beck and Al Blumstein, the principal sources of prison growth between 1980 and 2000 were in six major crime types: murder, sexual assault, robbery, assault, burglary and drug offenses (see Figure 2). About half of the total growth is attributable to an increase in the prison-commitment rate (prison admissions per 100 adult arrests), and the other half is due to increased time served. This is despite the fact that each factor's influence varied by decade, with increasing commitments accounting for more of the growth in the 1980s, and time served accounting for more of the growth in the 1990s. (1) Since 2000, there has been stability in incarceration rates, except for incarceration of drug offenders, which has declined after decades of rapid growth.
State-level analyses have uncovered additional factors, many of which are common among states. For example, the Ohio Department of Rehabilitation and Correction's (ODRC) Bureau of Research and Evaluation discovered that over the past 15 years, its female prison population increased by nearly 60 percent. Examination of the reasons for this growth found that 39 percent of female prison inmates were probation violators, which was nearly double the male rate. The rate at which females were committed to prison for drug-possession offenses was just over 19 percent, also double the rate for males. Heroin use and serious mental illness additionally affected the female prison population to a greater degree than the male prison population.
Reducing prison populations
The implications of the foregoing national data are clear: To reduce mass incarceration, decision-makers must address the key drivers of past growth--prison commitments and time served. Detailed state-level analyses provide additional critical data to inform decision-makers on the specific contributors to prison population growth locally.
Ohio's experience is one example of how this may be done. Analysis by ODRC found the top incarcerating offenses for male and female offenders were drug possession, drug trafficking, burglary and grand theft; robbery rounded out the top five offenses for male offenders, and illegal manufacturing of drugs was the fifth most common offense for female offenders. (2) This knowledge of the crimes driving prison admissions provides a central focus for rehabilitation efforts around the state.
Substance abuse and mental health constitute a second critical focus for efforts in Ohio; ODRC's Bureau of Research and Evaluation found that over 10,000 inmates in that state are on mental health caseloads. Over 30 percent of male offenders, and 61...