By Michael Topper and Toshio Ferrazares

ShotSpotter is an acoustic gunfire detection technology utilized by police departments in over 150 cities world-wide with the intention of rapidly dispatching police officers to violent crime scenes in an effort to reduce gun violence. In Chicago, this amounts to approximately 70 instances per-day whereby officers are immediately dispatched to potential instances of gunfire. However, this allocation diverts police resources away from confirmed reports of 911 emergencies, creating delays in rapid response—a critical component of policing with health and safety implications. In this paper, we utilize variation in timing from ShotSpotter rollouts across Chicago police districts from 2016-2022 to estimate the causal effects of ShotSpotter on 911 emergency response times that are designated as Priority 1 (immediate dispatch). Using comprehensive 911 dispatch data from the Chicago Police Department, we find that ShotSpotter implementation causes police officers to be dispatched one-minute slower (23% increase) and arrive on-scene nearly two-minutes later (13% increase). Moreover, these effects are driven by periods with fewer police on-duty and times of day with larger numbers of ShotSpotter-related dispatches. Consequently, when responding to emergency calls, police officers’ success rate in arresting perpetrators decreases by approximately 9%, with notably large decreases in arrests for domestic battery (14%).

Job Market Paper, 2023. 75p.

Congressional Research Service

In times of crisis, people call 911 to receive emergency assistance. For decades, the 911 system has operated using legacy infrastructure (i.e., telephone calls through the public switched telephone network). In the 2000s, local governments and public safety officials identified the need to keep pace with emerging communications technologies and communication formats that consumers use in daily life (e.g., texts, videos, photos). As such, some public safety answering points (PSAPS, also known as 911 centers) are upgrading their infrastructure to Internet Protocol (IP)-based systems—referred to as Next Generation 911 (NG911). When fully transitioned, NG911 is anticipated to enhance emergency response service, making it easier for the public to report emergency needs and for first responders to receive rich information. This includes multimedia transmissions—such as text messages, streaming video, and photos—directly from the public to PSAPs, which can enhance situational awareness for 911 telecommunicators in dispatching emergency response. Additionally, NG911 allows for interoperability with other PSAPs so that calls can be transferred to other centers for response—for example, in the event of call overload during a disaster—and also for interconnection with the First Responder Network Authority (FirstNet) to seamlessly transfer data directly from PSAPs to first responders in the field.

Congressional Research Service. https://crsreports.congress.gov R48015. 2024. 19p.

By City of Chicago, Office of Inspector General

The objectives of the inquiry were to determine the completeness rates of CPD response times recorded by CPD and the Office of Emergency Management and Communications (OEMC), and to identify factors contributing to missing response time data for 911 calls for CPD service.

As a result of this inquiry, OIG found that CPD’s data collection of 911 response times is incomplete; the Department fails to record timestamps for various statuses throughout the dispatch and police response for a substantial number of 911 calls. Calls for high priority emergency events had a higher rate of recorded response times for all statuses that occur during a unit’s response (Acknowledge, Enroute, and On-scene) compared to calls for events with a lower priority classification. The timepoint in the police response process that is least often recorded is the On-scene time, or the time when the responding CPD unit arrives at the location of service; this remains true regardless of call priority level or geographic location. The On-scene status is the last time point in the sequence of events before responding members engage with an emergency event, which may contribute to the low On-scene time completeness rates. Additionally, the interface of the Computer Aided Dispatch (CAD) system, which records a timestamp when CPD members enter their response status, displays the response status buttons sequentially, and is dependent on the previous status in the process being entered.

Chicago: City of Chicago, Office of Inspector General, 2023. 30p.