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Global Terrorism Database Coding Notes: Las Vegas 2017

UPDATED 10/07/19: In January 2019, the Federal Bureau of Investigation Behavioral Analysis Unit published its final report on the 2017 Las Vegas attack.[4] Although it did not address or refute the witness accounts described below, or offer evidence of alternative explanations for the attack, the report concluded that "there was no single or clear motivating factor."[5] Due to mixed information about the motives for the attack, we included the record in the GTD and classified it as “doubt terrorism proper.”

On October 1, 2017, an assailant opened fire on the Route 91 Harvest Festival concert from the Mandalay Bay Hotel in Las Vegas, Nevada. Authorities identified the assailant as Stephen Paddock. He killed 58 people and injured more than 850 others before he shot and killed himself.

In the aftermath of the attack, investigators, journalists, and analysts sought to understand why Paddock carried out this horrific act of violence, but details about his motive were scarce despite the severity of the attack and exceptional tactics. Here we chronicle the information-gathering and decision-making process that led START’s Global Terrorism Database (GTD) team to include this in the database as an act of terrorism.


  • 10/01/17: Stephen Paddock opened fire on the Route 91 Harvest Festival.
  • 12/07/17: The GTD team began reviewing news articles published in October containing information potentially relevant to acts of terrorism. This is the first step of the data collection workflow in which researchers make decisions about whether or not events satisfy GTD inclusion criteria. Because the Las Vegas attack was a major event with an unknown motive, we created a placeholder entry so we could begin to organize source documents about the event. We coded the inclusion criteria as not satisfied so the record would not be promoted to the database without additional evidence.
  • 02/22/18: After several months passed and investigators reported preliminary findings with no specific details about Paddock’s motive[1] we flagged the record for deletion in the database during routine quality control reviews of the October 2017 data.
  • 05/17/18: We came across media reports that the Las Vegas Metropolitan Police Department (LVMPD) had released 1,200 pages of documents, including witness statements, following an order from the Nevada Supreme Court in response to a lawsuit filed by several media organizations.[2] Although this information was only reported on briefly, numerous media outlets covered the document release and the new information provided. Over the course of the next two weeks, we reviewed this coverage and the underlying witness statements regarding the assailant’s state of mind.
  • 05/30/18: The GTD team resurrected the record of the Las Vegas attack in the database, adding new sources describing the relevant information provided in the witness statements.
  • 08/01/18: START finalized and published the 2018 release of the GTD, including data through 2017 and updates to earlier cases.
  • 08/03/18: The LVMPD released a final criminal investigative report regarding the October 2017 attack, “authored to provide the reader with more information about who, what, when, and where. Regretfully, this report will not be able to address the why.”[3]
  • Updated 10/07/19: In January 2019, the Federal Bureau of Investigation Behavioral Analysis Unit published its final report on the 2017 Las Vegas attack.[4] Although it did not address or refute the witness accounts described below, or offer evidence of alternative explanations for the attack, the report concluded that "there was no single or clear motivating factor."[5] Due to mixed information about the motives for the attack, we included the record in the GTD and classified it as “doubt terrorism proper.”

Global Terrorism Database Inclusion Criteria[6]

The GTD defines terrorism as “the threatened or actual use of illegal force and violence by a non-state actor to attain a political, economic, religious, or social goal through fear, coercion, or intimidation.” (p. 10) To apply this definition, we parse it into a series of inclusion criteria.

Mandatory inclusion criteria:

  • The incident must be intentional – the result of a conscious calculation on the part of a perpetrator.
  • The incident must entail some level of violence (includes property violence) or the threat of violence.
  • There must be sub-national perpetrators.

At least two of the following criteria must be met:

  1. The act must be aimed at attaining a political, economic, religious, or social goal. In terms of economic goals, the exclusive pursuit of profit does not satisfy this criterion.
  2. There must be evidence of an intention to coerce, intimidate, or convey some other message to a larger audience (or audiences) than the immediate victims.
  3. The action must be outside the context of legitimate warfare activities, i.e. the act must be outside the parameters permitted by international humanitarian law (particularly the admonition against deliberately targeting civilians or non-combatants).

In the case of the Las Vegas attack, the mandatory inclusion criteria are satisfied and criterion 3 is satisfied. The key question is about criteria 1 and 2, which are often closely related. While one might argue that the dramatic tactics used in the Las Vegas attack alone would satisfy criterion 2, we typically refrain from jumping to that conclusion because it is possible that the perpetrator adopted these extraordinary tactics for other reasons. The following notes outline our decision making regarding criteria 1 and 2.


This is certainly a difficult and unusual case, with an enormous impact on the data. Although we finalized the GTD data before the LVMPD released their August report, at this point we do not believe it changes our assessment.

  • The GTD is based on open source media reporting, which includes but is not limited to reporting from law enforcement officials. It also includes, for example, journalistic assessments and witness accounts. Law enforcement and government officials throughout the United States and around the world have various thresholds for identifying definitive motives and classifying events as terrorism. Our aim is to transcend these variations by basing our decisions on the characteristics of attacks as comprehensively as possible, rather than basing our decisions solely on the conclusions of law enforcement officials.
  • The reporting that substantiates our decision to include the Las Vegas attack in the GTD was extensively (yet briefly) documented in May 2018, including by CBS, the Guardian, ABC, Fox, the Wall Street Journal, Breitbart, etc. Until that point, we fully expected we would not include this case in the GTD. Although we shared the frustration of many that we did not understand why the attack took place, our decision to exclude the Las Vegas attack was neither a disappointment nor a relief. We prioritize consistency and adherence to documented coding practices over all else; otherwise, the data we produce would be useless. We base coding decisions on available evidence, synthesizing conflicting information and accounting for source credibility, not on personal notions of what terrorism looks like.
  • While witness reports after the fact are not necessarily as reliable as statements made by the perpetrator during the attack, we found it compelling that the official investigative documents reported that at least two apparently unrelated witnesses heard Paddock make ideological statements in the days and weeks leading up to the attack. These statements included:
    • A transcript of an interview on 11/07/17 with an unidentified individual who reported meeting Paddock several weeks before the Las Vegas attack. The purpose of the meeting was to sell Paddock schematics for an “auto sear” device to convert a semi-automatic weapon into an automatic weapon:[7]
      • The witness provided detailed information about the meeting, including where it took place, when it took place, the reason Paddock’s name was memorable, a physical description of Paddock, the fact that Paddock showed identification to verify that he was a Nevada resident, and that based on their brief conversation Paddock seemed to have “plenty” of money.
      • The transaction never took place because the witness was alarmed by Paddock’s statements, including "Somebody has to wake up the American public and get them to arm themselves… Sometimes sacrifices have to be made.” According to the witness, who cut the meeting short, Paddock also “kept carrying on about anti-government stuff…FEMA stuff…and he was saying how Katrina…was just a dry run for law enforcement and military to start kicking down doors and confiscating guns.” (p.56)
      • The detectives conducting the interview lightly interrogated the witness, focusing on questions about the circumstances of the meeting, whether Paddock seemed to be working alone, and whether Paddock said anything about what he was planning to do. Aside from one question about whether Paddock explained why Hurricane Katrina upset him, the detectives asked no follow-up questions about Paddock’s anti-government statements. In response, the witness reiterated the assertion that Paddock believed the public needed to arm themselves because of “FEMA camps” and that “the government’s gonna crack down on everybody who has weapons.” (p. 69).
    • An account from a woman who described overhearing a man (whom she noted at the time physically resembled the actor Clancy Brown) at a diner a few days before the shooting. She identified him as Paddock and reported that he was with a second man. The two men referenced Waco, anger about Ruby Ridge, gold fringe on flags in courtrooms (a Sovereign Citizen conspiracy), and anger at the federal government and ATF. She indicated that she was not aware of the significance of some of these references. Compared to the first, this statement is much shorter, somewhat more vague, and lacking in interrogation and affirmative identification of Paddock by name, but appears to be thematically consistent.[8]
  • The LVMPD’s August report[9] states:
    • "This report was authored to provide the reader with more information about who, what, when, and where. Regretfully, this report will not be able to address the why." (p. 9)
    • “Suspectology is the gathering of information to help establish the identity of a suspect and motive in a crime. Suspectology can be developed through interviews with family, friends, and associates and also through analysis of data collected about a subject. Agents with the FBI’s Behavioral Analysis Unit (BAU) responded to gather information and help with Paddock’s suspectology. At the time of this report, the FBI’s BAU assessment of Paddock is not complete and will be released by the FBI at a later date.” (p. 111)
    • "No suicide note or manifesto was found. Of all the evidence collected from rooms 32-135 and 32-134, there was no note or manifesto stating Paddock’s intentions." (p.126)
    • "There was no evidence of radicalization or ideology to support any theory that Paddock supported or followed any hate group or any domestic or foreign terrorist organization. Despite numerous interviews with Paddock’s family, acquaintances and gambling contacts, investigators could not link Paddock to any specific ideology." (p. 126)
    • "As stated earlier in this report, investigators were unable to uncover or discover what Paddock’s motive may have been. While motive may have eluded investigators, there were certain indicators of intent shown by Paddock which lead up to the mass shooting." (p. 127)
  • We don’t know why the August report does not mention the witness statements released in May. The reporting from May indicates that law enforcement was compelled by the Nevada Supreme Court to release the documents, and that they resisted doing so because it was "costly and time-consuming, and… could disclose investigative techniques."[10] We have looked for reports indicating that the police viewed the information as particularly inaccurate, unreliable, or misleading, and did not find any.
  • Some of the LVMPD comments regarding motive suggest they may consider evidence of motive to be an explicit/definitive/conclusive explanation beyond a reasonable doubt (e.g., suicide note/manifesto). This is not a threshold we use for GTD decision making. We also do not know whether establishing a motive, either specific or general, was a top priority for the LVMPD report, given the massive scale of the multi-agency investigation into the sequence of events up to and including the attack itself. Since the Las Vegas attack, we have had several discussions with law enforcement officials unrelated to the investigation who indicate that their focus is principally on criminal conduct and public safety, therefore familiarity with coded language about things like FEMA camps and fringe on flags in courtrooms is not typically part of their remit.
  • The GTD inclusion criteria do not require that the perpetrator support or follow any hate group or domestic/foreign terrorist group. Lack of evidence of radicalization--a cognitive process--is not evidence of lack of radicalization.
  • The LVMPD report does not offer information that negates the documentation released in May. In cases where there is conflicting evidence to suggest an ideological motive as well as evidence to suggest a non-ideological motive, we typically mark the record as "doubt terrorism proper" in the GTD. This allows analysts whose inquiry warrants a more conservative definition of terrorism to easily exclude these events. However, in this case the latest LVMPD report is neutral on the issue of motive and does not conclude with an alternative, non-ideological motive for the attack. As it stands, the only evidence currently available to us that addresses the specific motive of the attack (the May reporting) suggests a strong likelihood that Paddock was ideologically motivated.
  • Although our decision making on this case would be more concrete if these sentiments had been verbalized by Paddock publicly in connection with the attack, it would be highly speculative to simply disregard them. In fact, we added 10,900 terrorist attacks to the GTD for 2017 and this level of detail and investigation far surpasses what we typically have access to. In some instances, those close to perpetrators are aware of their adoption of a violent extremist ideology; however, there are many cases in which perpetrators succeed at keeping violent intentions mostly to themselves.


Reasonable people can review all of the available information and come to different conclusions on the appropriate interpretation of the evidence. This is why the GTD team values transparency and takes proactive steps to promote transparency, including publication of the GTD Codebook and publication of the raw data and source references.[11] These practices facilitate robust discussion about real implications of methodological decisions for scientific inquiry and policy. Importantly, several misconceptions require clarification.

  • Witness statements are not evidence.

Witness statements are certainly evidence. It is worth noting that in this case the witness observations that support our conclusions were not general, speculative, off-handed comments made to journalists (although those may have value as well). These witness statements were made to detectives in the course of an official investigation into the attack. They describe in some detail events that took place while Paddock was planning the attack and specifically in the course of carrying out preparations for the attack (attempting to purchase auto sears). They are not months or years removed, or out of context. Furthermore, the GTD team does not adopt a legal threshold of proof beyond a reasonable doubt for inclusion in the database.[12] We evaluate as much information as we can, as critically as we can, and make a determination based on a preponderance of evidence.

  • The GTD team included the Las Vegas attack in the database because of its particularly terrifying nature and the fact that it resulted in mass casualties.

Neither the lethality of an attack nor how terrifying it is has any bearing on the GTD inclusion criteria. Those familiar with the GTD will recognize that the database includes numerous non-lethal attacks and that numerous attacks, both deadly and terrifying, have taken place and not been included in the GTD due to a lack of evidence that the inclusion criteria were satisfied. There is no reason for us to have altered this practice in the case of the Las Vegas attack.[13]

  • The GTD team blindly relies on press reporting, including early reports on numbers of casualties, and claims of responsibility.

The GTD is collected on a lag of approximately two to five months behind real time. When START receives inquiries about accelerating the delivery of the GTD, one of the key points of caution we typically raise is the need for information to unfold before codifying it. Our workflow supports routine updating of attack details as new information becomes available. For particularly complicated attacks, we often wait until the last possible moment before finalizing and publishing the data to confirm that our inclusion decisions are consistent with the latest reporting.

If we blindly relied on press reporting, we would have attributed the Las Vegas attack to the Islamic State based on widely reported claims from Amaq, Islamic State’s propaganda arm, that Paddock was a “soldier of the caliphate.” We did not rush to such conclusions, noting that it is not uncommon for Islamic State representatives to overstate their role in violent attacks, even when there is no evidence to support a claim.[14] Between October 2017 and May 2018 we reserved judgment on the Las Vegas attack. We routinely advised eager journalists that there was insufficient evidence and we needed to wait for as much information as possible to become available before making a determination. As always, if new evidence becomes available we will update the information in the database as appropriate.

  • If Paddock were an anti-government extremist, he certainly would have attacked the government, not country music fans in Las Vegas.

When the GTD team makes a determination about whether an act of violence is aimed at intimidating an audience to achieve a political, economic, religious or social goal, we consider many aspects of the attack, including information about the perpetrator as well as inferences that can be drawn based on the target. Terrorism is a strategic type of violence designed to undermine and manipulate societies and governments.[15] It involves tactical decisions that take into account both likelihood of success (hardened government targets are not especially easy to attack) and emotional response (fear and anger) from various audiences. As a result, these tactical decisions may initially seem counterintuitive. With this in mind, it is not as surprising that Paddock would target the group he thinks most likely to take up arms in response to a perceived threat… those he is trying to “wake up.”

  • The fact that this case is an outlier should be taken into consideration when deciding whether it should be included in the GTD.

The impact a case will have on the resulting data has no bearing on our assessment of the inclusion criteria. We aim to be especially thorough in our research for potentially complex or significant events, but we do not hesitate to include or exclude an event because we are concerned about its potentially unique impact on statistics. The story of terrorism in the United States is a story of outliers. Although the exact circumstances of the Las Vegas attack are certainly unusual, the attack happened. There is nothing opaque or misleading about including and referencing it in a statistical analysis of terrorism. It remains the responsibility of the beholder to interpret statistics about complex phenomena with nuance and awareness. Removing this particular case from the data would not absolve us of that responsibility. Statistics are a tool to help understand and communicate large amounts of complex information, not a crutch to allow us to be intellectually lazy.