Bail reform is having a national moment, with momentum for change growing as state and local governments respond to reports and research on the failings of their pretrial detention systems. New Jersey has led with one of the most ambitious reforms, posting an impressive 20 percent decrease in its pretrial jail population in the first year. However, a recent report from the state's courts warned that the program's costs pose a serious threat to its sustainability -- a troubling but unsurprising result of imposing the costs of pretrial services and monitoring on the court system.

The New Jersey report demonstrates both the promise of bail reform and the need to marshal evidence that shows legislatures and state budget offices why they should fund pretrial services. Reform-minded stakeholders must be able to overcome the "wrong pockets" problem -- the benefits of the new system, such as decreased jail costs, accrue to a different part of the system than the one implementing and paying for the change. The New Jersey report also surfaces the point that simply implementing pretrial release doesn't sufficiently address underlying causes: As the report points out, many individuals released from pretrial detention are in need of supports such as housing and mental-health and substance-abuse treatment. To be successful, reforms to pretrial detention must be paired with thoughtful development of pretrial services that help defendants avoid failure-to-appear citations and divert them to programs likely to reduce the need for incarceration overall.

The combination of the wrong pockets problem, the opportunity for improved services and the need to make a data-driven case for sustained funding suggest that jurisdictions contemplating bail reform might consider pay for success (PFS) demonstration projects as stepping stones to larger reforms. In PFS projects, governments agree to make payments for a program based on rigorously demonstrated metrics of success. The program costs are paid for by third-party funders that take on the risk of program failure: If the success metrics aren't met, the funders rather than the taxpayers lose their money.

Bail funds across the country are already doing heroic work using philanthropic and grassroots funding to demonstrate the benefits of allowing detainees to return to families, jobs and communities and developing models of supporting detainees in showing up for court. Like bail funds, PFS contracts are not a long-term solution to the challenges endemic in the current system. Rather, PFS could build on work done by bail funds and others by offering a set of tools that engage governments as partners in piloting innovations that require significant systems changes:

Capturing benefits: One of the core aspects of PFS contracts is their potential for breaking down barriers between siloed parts of government. For example, a PFS contract in pretrial detention reform could commit a government to tracking and capturing benefits generated outside of the court system, including reduction in jail usage. PFS contracts also allow governments to bridge the gap between the upfront spending on preventive services and the savings that are often generated farther in the future. A PFS project addressing chronic homelessness in Massachusetts, for example, allowed the state to invest in permanent supportive housing designed to eventually reduce the need for emergency shelter, smoothing the transition when the state was still paying for both.

Rigorous evaluation: Good PFS projects use rigorous evaluations and data analysis to track outcomes for individuals served as well as metrics such as provider performance and potential cost savings. So if the tested approach works, the implementing agency is armed with the data to explain to the state's budget office, legislature or judiciary why more support in the form of dedicated funding and permanent changes to existing practices may be warranted. PFS projects are best used to generate rigorous evidence about the outcomes of an intervention that, if successful, can be taken to scale through direct funding.

Improved services: PFS projects are not just performance contracts; they rest on creating outcomes-focused, data-driven improvements to the way individuals are served that last long beyond the specific project. Governments have leveraged PFS projects to use data to target interventions to the individuals most at risk for poor outcomes, improve the handoff between government and service providers to prevent individuals from falling through the cracks, and establish data-driven collaborations with providers to improve the outcomes of services. One of the main challenges of reforming pretrial detention practices, for example, is establishing effective pretrial services that, in addition to supervision and monitoring, may also include interventions such as sending text messages to remind releasees to appear for their court dates and even diversion or handoffs to social services such as community-based substance-abuse treatment.

Because PFS deals can be slow and costly to set up, a government should use them only if it thinks there are significant barriers to undertaking the reform directly. But for jurisdictions considering reforms to bail and pretrial detention and in need of additional groundwork around feasibility, infrastructure to capture savings or improvements to service-delivery systems, pay for success may be an approach worth considering.