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Comparing Individuals Who Engage in Violent Extremism and Similar Acts: What Research Sponsored by the National Institute of Justice Tells Us

NCJ Number
Kateira Aryaeinejad; Thomas Leo Scherer
Date Published
May 2024

This study provides analyzes findings across National Institute of Justice–sponsored research projects on individuals who engage in violent extremism.


This synthesis paper compares and contrasts the data and findings from National Institute of Justice–sponsored research projects on violent extremism, mass shootings, and bias crimes. NIJ’s funding for research has provided important opportunities to advance understanding of topics related to crime and justice within the United States. This comparison focuses both on the content of the data and on the creation and coverage of the data, examining findings from four research projects: the Profiles of Individual Radicalization in the United States (PIRUS) database of 2,226 individuals who demonstrated at least 1 of 5 extremist or radicalized behaviors; the Bias Incidents and Actors Study (BIAS) database of 966 adults arrested or indicted for bias crimes; the National Hate Crime Investigation Study (NHCIS) database of 1,230 hate crime cases; and the Violence Project dataset of 172 mass shootings. This synthesis first reviews the creation of each dataset and the types of information collected to better understand their generalizability and the ability to make comparisons across separate datasets. There are significant differences in the size, time span, and information of the four datasets, which limits the comparisons that can be made and necessitates caution in drawing strong conclusions from such comparisons. The datasets suggest some similarities in the individuals who commit bias crimes and mass shootings and display violent extremist behavior. The datasets also suggest some differences in the individuals who commit each type of offense or behavior. The comparison of individuals across categories also highlighted differences among individuals who committed the same type of offense. Comparing these datasets highlights their potential and their limitations, suggesting paths forward for future research. These projects not only contribute to the current understanding of these types of offenses and behaviors but also allow future research and programming to be conducted more effectively.