One of the most common alternatives to incarceration in the United States is community supervision in the form of parole: parole is the system by which incarcerated individuals, often due to good behavior, are able to leave incarceration prior to their court appointed sentence expiration. Offenders released on parole often are subject to a period of community supervision post release. or probation: probation refers to the suspension of an offender’s prison sentence. Offenders released on probation are typically the subject of some form of community supervision. . In 2021, almost 3.8 million adults (approximately 1 in 69) were under community supervision: a common alternative to incarceration in which an offender is allowed to continue to live in or return to their community provided that they are under some sort of monitoring (for example an ankle monitor or check-ins with a community supervision officer) . Of these, approximately 112,000 were re-admitted to prison, half for a new crime, and half for violating the rules of supervision (e.g., failing to pay fines, secure housing, or complete rehab programs). The latter kind of return to prison is referred to as a technical revocation.
These facts raise the important questions that motivate this paper: Will reducing the length of post-release supervision cut down on the rate of technical revocation? Going further, what would be the impact of such a reform, if any, on crime?
In this paper, researchers leverage the passage of the Safe-T Act (the “Act”) in Illinois to answer these questions. The Act, passed on February 20, 2021, initially reduced the standard supervision period for class 1-2 felonies (more serious crimes often involving violence like arson, burglary, and sexual assault) from two years to one. Later, on December 6, 2022, the Act was amended to reduce the standard supervision period for class 3-4 felonies (less severe felonies such as theft, aggravated assault, and forgery) from twelve to six months. This amendment created a natural experiment as class 3-4 officers saw a reduction in supervision time while class 1-2 offenders did not.
Using the class 1-2 prisoners as the control group, the researchers applied a difference-in-differences: a statistical method that estimates the causal effect of a treatment or shock by comparing changes over time between an affected group and a similar but unaffected control group approach to gauge the effects of the new policy treatment on class 3-4 offenders. The researchers find the following:
- On the 12-month horizon (a year post release), the total return rate for class 3-4 prisoners fell by roughly 10 percentage points from a baseline return rate of roughly 22%.
- This corresponds to a 45% reduction in
total returns. - The technical revocation rate fell similarly
by around 10 percentage points on the 12-month horizon. - The researchers found no impact on returns to prison associated with new crimes.
From here, the researchers ask what would happen if the state were to further reduce supervision terms from six months to three months. To answer this question the researchers use a competing risks model: a model that estimates the time-to-event of a specific outcome when the occurrence of another event can affect it. This method is used in contexts when subjects are at risk of mutually exclusive events (for example, an individual may die of a disease or a car accident but not both). that allows them to simulate the expected results of potential future reforms. They conclude that a further 3 month reduction would cause 12-month prison return rates to fall by an additional 5 percentage points.
With such a large population under mandatory supervision, fully understanding the program is important for policy makers. Finding no evidence that the policy harmed public safety, the researchers show that the Act could bring immense benefit to the state. From the reduction of technical revocations, the researchers estimate that the December 6, 2022, amendment to the SAFE-T Act reduced expenditure on supervision and incarceration by at least $65 million annually.