Technology Spotlight

Crime Data Explorer

An image of three digital devices with the Crime Data Explorer website on the screen.

The FBI’s Uniform Crime Reporting (UCR) Program has collected and reported crime data from participating states and agencies for more than 88 years. Over time, the technology law enforcement agencies use to report their crimes to the FBI evolved from mailed paper reports, to faxes, to e-mails, to automated real-time system-to-system links. As reporting to the UCR Program became less cumbersome, open access to the Internet led to high demand for more timely publication of crime statistics.

Conceived in 1929 by the International Association of Chiefs of Police, the UCR Program has met the nation’s need for reliable uniform crime statistics. In 1930, the FBI began collecting, publishing, and archiving this data. Seven offenses were selected for reporting by a small number of agencies each month and became the core group of crimes in the Summary Reporting System (SRS). These included crimes against persons or property, as well as those with and without violence, but the system’s design limited data on individual incidents.

By the 1980s, the highly aggregated SRS format had not kept up with emerging technologies that allowed for greater specificity for reporting crime. As participation grew in the UCR Program, the FBI created the National Incident-Based Reporting System (NIBRS)—a proposed solution to the limited practicality of SRS data. Because NIBRS can provide additional information on criminal offense statistics and promote constructive discussion, planning, and informed policing, the FBI has made the implementation of NIBRS a top priority.

The vision is for NIBRS to become the law enforcement community’s standard for quantifying crime. NIBRS is intended to help law enforcement and communities around the United States use resources more strategically and effectively. Since the implementation of NIBRS, the FBI has continued efforts to modernize the collection and dissemination of the highly disaggregated crime data.

As the UCR Program continues to evolve, a need has emerged for law enforcement, the media, academia, and the American public to easily search and display data within the UCR system. Today, the program accepts criminal data voluntarily submitted from over 18,000 law enforcement agencies. As a result, considerable efforts to improve the information available from the UCR Program have resulted in new endeavors to reinvent and modernize the data. To this end, program personnel implemented a system upgrade intended to improve the accuracy and timeliness of the crime data collection and delivery process. The FBI also championed a new project called the Crime Data Explorer (CDE).

Deployed in June 2017, CDE is a Web-based solution that enables the American public to view and interact with UCR Program data in a user-friendly way. CDE is designed for a spectrum of users from novice to expert, including the public, students, legislative staff, criminal justice advocates, journalists, open-data experts, civic technicians, researchers, and law enforcement.

CDE changes UCR data offerings from solely static publication tables to ad hoc, user-driven requests that enable interaction with national crime data in an easy, intuitive manner. It allows the user to query, view, and download crime-reported data submitted to the UCR Program in machine-readable and open-source formats. Anyone with access to the Internet can use CDE (no special training is required). It is designed to accommodate changing data standards and provide greater transparency around the UCR Program.

Currently, CDE uses UCR NIBRS and SRS data to provide new output with new features and capabilities. Recent updates to the pages of CDE have included—

  • development of a Law Enforcement Officers Killed or Assaulted Explorer page;
  • publication of the 2017 Crime in the United States annual data;
  • an improved application-programming-interface endpoint, which returns raw JavaScript Object Notation data in a more useable format; and
  • deployment of a new framework to improve system performance.

Current developments for release in 2019 include—

  • deployment of a Supplemental Homicide Reporting Explorer page;
  • implementation of the Age, Sex, Race, and Ethnicity of Persons Arrested Explorer page;
  • publication of preliminary semiannual UCR data; and
  • creation and deployment of “data stories,” which will focus on identifying a small subset of NIBRS data concentrated on a specific topic.

The first step in understanding crime in the United States is to gather and publish better data related to those incidents and offenses that threaten public safety. CDE allows all users of crime data to easily review, analyze, and understand incidents of crime and its impact on the nation.

Lora Klingensmith, management and program analyst in the FBI’s Uniform Crime Reporting Program, prepared this Technology Spotlight. She can be reached at

“CDE allows all users of crime data to easily review, analyze, and understand incidents of crime and its impact on the nation.”