Terrorism and Targeted Violence (T2V) in the United States is a project housed at the National Consortium for the Study of Terrorism and Responses to Terrorism (START) the University of Maryland that seeks to provide policymakers, practitioners, researchers, journalists, and the general public with data and analysis on violent events occurring in the United States and its territories that are designed to have a significant impact on public safety and/or the security of critical infrastructure and key community services. Consistent with the Department of Homeland Security's Strategic Framework for Countering Terrorism and Targeted Violence Implementation Plan, the objective of T2V is to create robust, comprehensive data that are widely accessible to a variety of audiences and to provide critical insights on key questions about patterns of targeted violence in the United States.
From February 2024 through March 2025, the T2V project was funded by the Department of Homeland Security Science and Technology Social Science Technology Center as Task 1 of "Terrorism and Targeted Violence Research and Evaluation" (award #24STFRG00019). The project is now sustained through revenue generated by subscription site access and data licensing fees. The views and conclusions of the project should not be interpreted as necessarily representing the official policies, either expressed or implied, of the U.S. Department of Homeland Security, the University of Maryland, or START.
The data spans from January 2023 – August 2025 and is currently ongoing for recent months. We plan to collect data for previous years retroactively.
No, the T2V data only include events that occurred within the United States and its territories (e.g., Puerto Rico).
To have access to enough reliable information to determine if an event meets the T2V inclusion criteria, as well as to extract the event's relevant details, it is necessary to collect the data on a time lag. We anticipate that T2V data collection will get closer to real-time in the coming months, but we will maintain at least a one-month time lag to ensure data accuracy.
The T2V projects uses the definition of targeted violence found in the Department of Homeland Security's 2019 Strategic Framework:
"Any incident of violence that implicates homeland security and/or U.S. Department of Homeland Security activities, and in which a known or knowable attacker selects a particular target prior to the violent attack. Unlike terrorism, targeted violence includes attacks otherwise lacking a clearly discernible political, ideological, or religious motivation, but that are of such severity and magnitude as to suggest an intent to inflict a degree of mass injury, destruction, or death commensurate with known terrorist tactics. In the Homeland, targeted violence has a significant impact on the safety and security of our communities, schools, places of worship, and other public gatherings."
The T2V database includes successful, failed, and foiled events that meet the following inclusion criteria:
T2V events generally fall into the following categories:
With the exceptions of public mass violence and other targeted violence, these categories are not mutually exclusive. For instance, an act of terrorism can also be coded as a premeditated hate crime.
The "public mass violence" and "other targeted violence" categories are only used if an incident does not fall into one of the other event types. For example, an act of terrorism that results in mass casualties would not be coded as "public mass violence" in the T2V data but rather the event would be coded simply as "terrorism."
The T2V data do not include:
Yes, the T2V data include violent plots that were foiled by law enforcement during their planning stages. For a foiled plot to be included in the T2V data, there must be evidence that the perpetrator(s) identified a potential target or targets for the attack and engaged in at least one mobilization activity in preparation for committing the crime. Evidence of mobilization is derived primarily from court records, including affidavits written in support of criminal complaints, indictments, and memoranda written in support of pretrial detention, plea agreements, and sentencing.
Mobilization indicators include:
The T2V data do not include incidents in which a perpetrator made a threat of violence but did not engage in at least one activity that indicates they were preparing to act on the threat. The T2V data do not include events that are described as "hoaxes" or "not credible" by law enforcement or other officials with detailed knowledge of the events.
Yes, the T2V data include failed attacks. Failed attacks are defined as premeditated incidents in which the perpetrators attempted but failed to successfully deploy weapons due to technical malfunctions or operational errors (e.g., an explosive device was planted at or near a target but failed to detonate).
The T2V database defines a successful incident as one in which the perpetrator(s) of the crime deployed a weapon (i.e., fired a gun, detonated an explosive device, ignited a fire, etc.) against a target. Success is not defined in terms of the perpetrator's tactical or strategic goals. For instance, an event in which a perpetrator detonates an explosive device in a building, but fails to hurt or kill anyone, would be coded as a successful attack even if the assailant's goal was to cause mass casualties.
Mass violence is defined in the T2V database as an event in which the perpetrator intended to commit, or committed, an attack resulting in four or more casualties (deaths or injuries). Attacks involving the (planned) use of non-lethal weapons (pellet guns, smoke grenades, etc.) are not coded as mass violence unless they were deployed in an attack and caused four or more injuries.
Following the standard established by the Global Terrorism Database, "Incidents occurring in both the same geographic and temporal point will be regarded as a single incident, but if either the time of occurrence of incidents or their locations are discontinuous, the events will be regarded as separate incidents." Individual events are flagged in the T2V data if they are part of a string of attacks committed by the same perpetrator(s). A foiled plot is treated as separated incidents if the plan involved attacking multiple discrete targets. Including these plots and attacks as separate incidents in the T2V data allows for the accurate coding of the locations and targets of violent events in the United States.
Yes, the T2V data include terrorist attacks that meet the Global Terrorism Database's definition of terrorism: "the threatened or actual use of illegal force and violence by a nonstate actor to attain a political, economic, religious, or social goal through fear, coercion, or intimidation." For more information, see the GTD codebook at https://www.start.umd.edu/sites/default/files/2024-10/Codebook.pdf.
The T2V data include hate crimes that:
Hate crimes that are spontaneous, unplanned, or occur after chance encounters are not included in the T2V data. Moreover, hate crimes that do not involve the potential for violence (e.g., vandalism, denial of housing, etc.) or harm to property to such a degree to render the property physically inoperable are not included in the T2V data.
Yes, the T2V data include violent or potentially violent events that occur at educational institutions as long as:
School-based violent incidents related to interpersonal disputes are not included in the T2V data unless the events had a direct impact on a population beyond the intended targets of the attacks. For instance, fights between students on school property are generally not included in the T2V data. However, students who plan to commit, or commit, mass casualty attacks as revenge for being bullied are included in the T2V data.
Yes, the T2V data include violent or potentially violent events that occur at places of work as long as:
Yes, the T2V data include attacks targeting the 16 critical infrastructure sectors identified by the Cybersecurity and Infrastructure Security Agency, as well as vital community resources, such as schools and places of worship.
The T2V data only include attacks on critical infrastructure or key resources if:
Vandalism or other crimes that did not disrupt the functionality of the infrastructure are not included in the T2V data.
Yes, the T2V data include attacks on places of worship, such as churches, mosques, and synagogues, as long as they meet the T2V inclusion criteria above and had the potential to physically harm people inside the facilities and/or to render the property unusable. Places of worship are considered key community resources in the T2V data, and thus we err on the side of inclusion when they are targeted in criminal events, even if source materials do not provide or confirm the exact motives for the crimes.
The T2V database does not include violence that occurs at protests or demonstrations unless there is clear evidence that the perpetrators of the violence planned the attacks prior to attending the events. For instance, a physical assault that follows an argument between protesters and counter-protesters would not be included in the T2V data. However, an incident in which an individual plans to attend a protest or demonstration for the expressed purpose of committing a violent attack would be included in the database. In some cases, premeditation is determined based on the perpetrators' statements or the results of criminal investigations into the events. In other cases, premeditation is inferred from the types of weapons used in the acts (e.g., events are assumed to be premeditated when the perpetrators of the attacks use explosive devices or other complex weapons that require assembly).
The T2V database does not include events that were result of interpersonal or intimate partner disputes unless those incidents also impacted victims who (1) were not participants in the disputes or (2) did not have prior relationships with the perpetrators of the attacks. For example, if a perpetrator were to target their romantic partner at their place of work and their partner was the only victim in the attack, the incident would not be included in the T2V data. If, however, a perpetrator targeted a romantic partner at their place of work and also attacked their partner's co-workers, resulting in a mass casualty event, the incident would be included in the T2V data.
The T2V data dashboard currently provides users with a descriptive summary of all events, as well as coded information on dates, locations, outcomes (i.e., successful attack, foiled plot, and failed attack), event types (e.g., terrorism, school-based violence, workplace violence, etc.), types of intended attacks (i.e., mass casualty, low casualty, and property crime), target types, weapon types, number of perpetrators, ages, casualties (total deaths, total injuries, perpetrator deaths, perpetrator injuries, victim deaths, and victim injuries), and prosecution jurisdiction.
The T2V database uses the following coding scheme for classifying target types:
A value of -99 in the T2V data indicates that researchers were unable to find information in public sources for a specific variable related to the event.
You may request access to the data dashboard or a downloadable CSV file via subscription site access and data licensing fees here: https://www.start.umd.edu/t2v/account/request-access/.
All inquiries about the T2V project can be sent to t2v@umd.edu.
Yes, we encourage researchers, analysts, scholars, and journalists to use the T2V data in their work. Use of the data signifies your agreement to our Terms of Use, which include properly citing the T2V database and refraining from redistributing or republishing the data for commercial or non-commercial uses. Using the T2V data for commercial purposes is a violation of the project's Terms of Use.
No, using the T2V data for commercial purposes is a violation of the project's Terms of Use. A license must be obtained to use the T2V data for commercial purposes. Please contact t2v@umd.edu to inquire about licensing the data for commercial use.
No. Users should not infer any additional actions or results beyond what is presented in a T2V entry. Specifically, users should not infer an individual associated with a particular incident was tried and convicted of terrorism or any other criminal offense. If new documentation about an event becomes available, an entry may be modified, as necessary and appropriate.
Yes. Please use the following citation if using the T2V data in your own research/ publication:
National Consortium for the Study of Terrorism and Responses to Terrorism (START). (2025). Terrorism and Targeted Violence (T2V) in the United States [Data file]. Retrieved from https://www.start.umd.edu/t2v
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