U.S. flag

An official website of the United States government, Department of Justice.

Audio Analytics and Other Upgrades in Correctional Surveillance Systems

NCJ Number
Date Published
February 2021
10 pages

This article highlights the Minnesota Department of Corrections’ (MnDOC’s) experience with a system update, the benefits and challenges of the new system, and recommendations for the field regarding how to improve the effectiveness and efficiency of correctional surveillance systems.


In 2017, the Urban Institute began working with the Minnesota Department of Corrections (MnDOC) to evaluate its efforts to optimize the surveillance systems in the housing units of two state prisons: Minnesota Correctional Facility–Stillwater (STW) and Minnesota Correctional Facility–Moose Lake (ML). Improvements included new high-definition cameras, repositioning of existing cameras, software and hardware updates, and the installation of aggression detection technology (a type of audio analytic technology) in one of the units. To understand staff experiences with the upgraded surveillance systems, we conducted numerous site visits to observe the use of the systems and interviewed correctional staff and leadership at ML and STW. The interviews and observations occurred before, during, and after the facilities upgraded and installed new surveillance technologies in the intervention housing units. Our goal was to collect information on staff’s experiences with the upgraded surveillance systems and identify recommendations for optimal use of surveillance systems in the correctional setting. We conducted semi structured interviews with leadership and staff at both housing units who directly use or work with video surveillance and/or have been involved in decision-making around the camera upgrades and audio analytics implementation. This included interviews with prison wardens, correctional officers, security leads, and information technology (IT) leads involved in the installation, configuration, and maintenance of infrastructure and cameras. The interviews focused on staff’s perceptions of safety within the two facilities, violent and nonviolent misconducts, the transition to the new cameras and upgrades, logistical and training needs, and perceived benefits of and challenges with the surveillance upgrades. Interviews with in-depth facility observations, which included a walk-through of the two facilities to observe the new cameras, camera placements, and viewing stations. In ML, researchers also saw a demonstration of the aggression detection technology and how staff view and manage alerts in the viewing stations. Researchers also requested and received logs of the alerts received by ML staff through the aggression detection technology, which included the time and location of each incident and information on how each was classified upon investigation (i.e., as physical fights, shouting/verbal altercations, nuisance alerts, or false alerts). The interviews and observations revealed that the upgraded technology had benefits and challenges. Main findings are presented in this report. (Published abstract provided)


Date Published: February 1, 2021