The 911 Call Processing System: A Review of the Literature as it Relates to Policing (PDF)
Authors – S. Rebecca Neusteter, Maris Mapolski, Mawia Khogali, and Megan O’Toole
Vera Institute of Justice – July 2019

Introduction

When people think of 911, they may think first of emergency medical services. But a significant portion of the 911 calls made every year in the United States are routed to police departments.

There’s only one problem: nobody knows how many.

The 911 system is complex and involves many actors. First there is the caller. He or she places a call for help that is connected to a call-taker. The call-taker gathers information about the emergency and inputs it into a system designed to identify the caller’s location and categorize the call. Next, a dispatcher (who may also be the call-taker, depending on the jurisdiction) uses this information to assign emergency responders to the location of the emergency. Once they arrive, the responders provide assistance. Even after that, the system is still gathering data: responders are filling out their own reports, comparing their assessment of the emergency to the call-taker’s, and logging the amount of time spent arriving at and then responding to the emergency.

With 911 systems capturing all of this information, it might seem like 911 would be easy to study, and there would exist a broad body of literature analyzing patterns among calls and helping police do their jobs. But 911 call centers (called public service answering points, or PSAPs) operate The development of PSAPs allowed 911 to spread rapidly through the United States, but today it is one of the greatest hindrances to actually understanding the system we use and its effects independently and locally. They cannot transfer calls to each other and, if your call is routed to the wrong PSAP—for example, if you are traveling near a state line and calling from a cell phone—they may not be able to send responders to your emergency. The development of PSAPs allowed 911 to spread rapidly through the United States, but today it is one of the greatest hindrances to actually understanding the system we use and its effects.

For this report, the Vera Institute of Justice (Vera) examined the body of literature that has developed as researchers have attempted to collect and study 911 data in the context of policing. Researchers have taken two main approaches to the study of the 911 system. First, there are studies using simplified, but more readily available, metrics such as call volume, call type, and response time. These studies allow researchers to draw broad generalizations about several jurisdictions at the same time, but are limited in their ability to inform about trends with any specificity—they simply collapse too many variables into too few categories. Then there are complex studies modeling caller behavior, call type patterns over time, and factors affecting the ability to respond in a timely fashion. These latter studies demonstrate the richness of 911 data available from individual jurisdictions, but are limited in scope because researchers can’t compare this data across jurisdictions. The report concludes with a call for research to fill gaps in the current 911 literature in order to chart a path forward using 911 data to improve police efficiency and provide the most effective and appropriate responses to true emergencies.