Incarceration Trends: Complexity and Continuous Improvement

Scrantonpajail Small
Lackawanna County jail, PA
Jail data is notoriously difficult to work with, and jails are used differently across the country.

We are in the process of making an improvement to the website that will address this problem, and will let users see when race data is partially or completely not known for a county. For Hennepin County, for instance, this would indicate that since 2001, more than half of the jail population was missing race data.

Jail data is notoriously difficult to work with. Thousands of jails systems across the country use a variety of data management systems. And while conversations about jails often focus on pretrial detention, the reality is that jails are used differently across the country. Some are nearly exclusively used to hold pretrial detainees, while in others the majority of the people held are serving a sentence. Adding further complexity, some jails rent beds to other state, local, and federal corrections systems—thereby influencing the county’s growth trends and incarceration rate on a per capita basis. Furthermore, when people are transported from one jail jurisdiction to another, they are “counted” in the jail where they are held, thereby undercounting the number of people detained by county justice systems that use other counties’ jails.

Consequently, it is usually valuable to review a county’s prison admission and prison population data—also available in the Incarceration Trends data tool—to get a “reality check” of the jails data. Because nearly everyone who goes to prison passes through a local jail first, prison trends are often similar to jail trends, and dramatic differences merit further inquiry. Prison data, which is sourced from the administrative records of state prison systems, is generally more complete and comprehensive than the jail survey data.

In the coming year, Vera will continue to work with state and local governments and advocates to identify gaps in data, use publicly available data sources to share fresher insights, and innovate and expand data collection across the country. We believe that transparent, accurate, timely data about how our nation is using local jails and the way in which they’re impacting communities is vital—for a healthy democracy, to challenge assumptions, and to craft truly meaningful reforms at the state and local level.

But we also recognize that data alone does not tell the whole story. The lived experiences of communities and individuals whose lives have been directly impacted by the rise of mass incarceration are another way to “reality check” what we see in the existing data, and to help guide future policy. So, as we continue to explore the data, we do so in a broad spirit of partnership with civil society and civil servants alike, with the shared goal of using data and knowledge to reverse mass incarceration. If that ambitious goal speaks to you, or if you ever have questions about what you’re seeing, we certainly hope you’ll be in touch. You can always reach us at