Application of the TRAP-18 Framework to U.S. and Western European Lone Actor Terrorists

The Terrorist Radicalization Protocol 18 (TRAP-18) is tested on a sample of 80 people who were convicted for Islamist activities in Germany between 2006 and 2017. In the study, perpetrators of terrorist attacks will be compared to persons who have been convicted of propagandistic and financial terrorist support and of joining a terrorist organization abroad. Statistical analysis of the results shows that there are significant differences between terrorist perpetrators and persons convicted of nonviolent Islamist activities, both in the number of TRAP-18 items and in the proximal warning behaviors "pathway," "last resort," "energy burst," and "novel aggression." Subsequent ROC analyses underline both the specificity and sensitivity of the instrument. AUC values range from .83 to .90 for the four different models (TRAP-18 and the warning behavior typology as weighted and unweighted models). The highest discrimination between Islamist attackers and the non-attackers is achieved by the weighted warning behavior typology. The values for sensitivity (se = .80), specificity (sp = .93), positive predictive value (p+ = .80), and negative predictive value (p− = .93) are extremely promising. Public Significance StatementThe study deals with the question of whether TRAP-18 is capable of distinguishing persons who have committed an Islamist act of violence from those who have taken on more supportive, nonviolent roles in the scene. The results show that this is the case. Specific behavioral patterns can be identified that are overly coincidentally common in violent terrorists. Likewise, terrorists show more warning behavior than those who have not committed a violent crime. Against this empirical background, TRAP-18 has proven to be an instrument with a high potential for successful early detection of Islamist-terrorist violence.

Section: Focus Method and Limitations Of The Present Studymentioning

confidence: 99%

Islamist terrorists in Germany and their warning behaviors: A comparative assessment of attackers and other convicts using the TRAP-18.

Böckler¹,

Allwinn²,

Metwaly³

et al. 2020

“…Multidimensional scaling (MDS) analysis has demonstrated the differential two-dimensional clustering of proximal warning behaviors when comparing North American terrorist attackers and other subjects of national security concern (Goodwill & Meloy, 2019). Questions have been raised concerning its ability to comprehensively code jihadist terrorists from open-source data in Europe (Brugh et al, 2020). However, another study found the TRAP-18 to have high sensitivity and specificity in the prediction of violence among a sample of German jihadist terrorists when compared to other nonviolent jihadists (Böckler et al, 2021).…”

Section: Methodsmentioning

confidence: 99%

Time sequencing the TRAP-18 indicators.

Meloy¹,

Goodwill²,

Clemmow³

et al. 2021

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.

“…In their article Brugh and colleagues recommended that one of the first steps should be to not apply such a rigid definition across all cases (as they did in their own study) in order to afford discretion and reduce the likelihood of a false negative. Research could, therefore, examine how others interpret and apply "clustering" (Brugh et al, 2020).…”

Section: Exploring How Evaluators Make Decisions About Priority Recom...mentioning

confidence: 99%

“…This may be explained by the fact that nine of the U.S. lone actors, compared to only one of the European lone actors, involved sting operations which produce all of information on various items related to the TRAP-18. Or the difference between the United States lone actors and the European lone actors may be due to the significant influence of Western (most notably, American) researchers in the terrorism field (Brugh et al, 2020). The findings by Brugh et al (2020) also indicated that there are potential challenges in completing the TRAP-18 when only relying on publicly available information.…”

mentioning

confidence: 99%

The feasibility and utility of the Terrorist Radicalization Assessment Protocol (TRAP-18): A review and recommendations.

Allely¹,

Wicks²

2022

The ability to accurately predict the risk of an individual committing an act of targeted violence is likely to be impossible given the low base rate of these acts (Goodwill & Meloy, 2019). Nevertheless, prevention is possible if there is a focus on fact-based behaviors, and threat management is in place. The Terrorist Radicalization Assessment Protocol (TRAP-18; Meloy, Habermeyer & Guldimann, 2015; Meloy, Roshdi, et al., 2015; Meloy & Gill, 2016; Meloy, 2017) is a collection of 18 behavior-based warning signs for terror incidents. There are eight proximal characteristics and 10 distal characteristics. The aim of this review was to identify studies which have utilized the TRAP-18 either prospectively (operational use) or retroactively or studies which have investigated the validity and reliability of the TRAP-18. A total of 17 relevant articles were identified in the review including six case studies and 11 empirical articles.