Time sequencing the TRAP-18 indicators.

Abstract

A time sequence analysis is conducted on 125 lone actor terrorists, most of whom mounted attacks in Europe and North America, utilizing the TRAP-18 (Terrorist Radicalization Assessment Protocol), a structured professional judgment instrument with demonstrable interrater reliability and criterion, discriminant, and predictive validity. Both frequency filters (>3) and coefficient filters (>.50) were applied to the data. Results indicate that virtually all distal characteristics, such as criminal violence, mental disorder, and ideology, preceded the proximal warning behaviors, such as pathway, fixation, identification, leakage, last resort, and directly communicated threats. Indicators that were "gatekeepers" and "turning point events" were also identified (Taylor et al., 2008). The time sequence analysis further validates the model of the TRAP-18 as a risk instrument for the assessment and management of lone actor terrorist violence. Public Interest StatementThis study applies a terrorist risk assessment instrument, the TRAP-18, to a large sample of lone actor terrorists using time sequence analysis: a method by which indicators of risk are organized in a temporal relationship with one another. It allows counterterrorism investigators to better understand the unfolding of risk indicators over time on the way to a terrorist attack, and helps prioritize the most dangerous cases.

TRAP-18 indicators validated through the forensic linguistic analysis of targeted violence manifestos.

“…The most prevalent indicators in the manifestos were leakage (100%), identification (93%), changes in thinking and emotion (93%), fixation (90%), last resort (87%), and framed by an ideology (83%). These findings are consistent with other studies on targeted violence attacks and the TRAP-18, such as Islamic terrorists in Germany (Böckler et al, 2020), North American terrorists and other subjects of national security concern (Meloy et al, 2019), violent versus nonviolent Sovereign Citizens in the United States (Challacombe & Lucas, 2019), and lone-actor terrorists from the United States and Europe (Meloy, Goodwill, et al, 2021;Meloy & Gill, 2016).…”

“…Changes in thinking and emotion is often a relatively longterm change in interpersonal behaviors, internal fantasies (often inferred through social media intelligence gathering), and emotions expressed toward the out-group (Matsumoto et al, 2017). As Meloy, Goodwill, et al (2021) wrote:…”

“…In a true sense, it is deliberate siloing so that the reader or listener will not know the exact plan of attack; it is good operational security. Pathway warning behavior is typically one of the most frequent “gatekeeper” indicators when more case data are available (Meloy, Goodwill, et al, 2021); when these results are applied to threat assessment of a manifesto, the absence of a pathway warning behavior should not be interpreted as an absence of risk, especially when identification and last resor t are present.…”

“…A principle structured professional judgment instrument for assessing the risk of a lone actor terrorist attack is the Terrorist Radicalization Assessment Protocol (TRAP-18; Meloy, 2017), which incorporates these proximal warning behaviors. The TRAP-18 has demonstrable reliability, and content, criterion, discriminant, and predictive validity in numerous studies (Allwinn et al, 2019; Böckler et al, 2020; Challacombe & Lucas, 2019; Goodwill & Meloy, 2019; Meloy et al, 2019; Meloy & Gill, 2016; Meloy, Goodwill, et al, 2021). Although there are a few terrorist risk assessment instruments, the TRAP-18 is the only one with established reliability and validity in the open source scientific literature.…”

Troubled waters: Domestic terrorism threat in the U.S. coast guard and the TRAP-18.

“…Typically this warning behavior is coded with the presence of either words or actions: a statement that implies a violent time/action imperative, or behaviors that indicate a foreshortened future (Meloy, 2017). In a time sequence analysis of the TRAP-18 indicators in 125 lone actor terrorists, last resort was temporally closer to an attack than several other warning behaviors, such as fixation and identification, but fell below the proximity coefficient threshold we established for the study in its temporal relationship to the attack (Meloy et al, 2021). The sheer amount of data and behaviors that translate into Mr. Hasson’s displays of pathway, fixation, identification, energy burst, and leakage add to the seriousness of the situation and suggest the potential of an attack, but the presence of such data does not absolutely predict an attack.…”