The Migration of Lynch Victims' Families, 1880-1930.

We examine the relationship between the lynching of African Americans in the southern United States and subsequent county out-migration of the victims' surviving family members. Using U.S. census records and machine learning methods, we identify the place of residence for family members of Black individuals who were killed by lynch mobs between 1882 and 1929 in the U.S. South. Over the entire period, our analysis finds that lynch victims' family members experienced a 10-percentage-point increase in the probability of migrating to a different county by the next decennial census relative to their same-race neighbors. We also find that surviving family members had a 12-percentage-point increase in the probability of county out-migration compared with their neighbors when the household head was a lynch victim. The out-migration response of the families of lynch victims was most pronounced between 1910 and 1930, suggesting that lynch victims' family members may have been disproportionately represented in the first Great Migration.

An Epidemiological Analysis of Terrorist Attacks in the Nordic and Baltic Countries from 1970 through 2020.

BACKGROUND: Russia's annexation of Crimea in 2014, and the recent Russo-Ukrainian war that started in 2022, were triggers that radically changed the perception of security in the Nordic and Baltic countries. The on-going Russian hybrid war has resulted in a renewed global interest in the safety and security of many countries (eg, the Nordic-Baltic Eight). The prospective North Atlantic Treaty Organization (NATO) membership of Finland and Sweden may drastically change the regional military and political landscape.The objective of this study was to identify and characterize all documented terrorist attacks in this region as reported to the Global Terrorism Database (GTD) from 1970 through 2020. METHODS: The GTD was searched using the internal database functions for all terrorism incidents in the Nordic-Baltic states: Denmark, Estonia, Finland, Iceland, Latvia, Lithuania, Norway, and Sweden.Temporal factors, location, target type, attack and weapon type, perpetrator type, number of casualties, and property value loss were collated. Results were exported into an Excel spreadsheet for analysis. RESULTS: There were 298 terrorism-related incidents from 1970 through 2020. Most attacks occurred in Sweden, followed by Norway and Finland. No entries were recorded for the Baltic states prior to their independency in 1991. The 298 incidents resulted in a total of 113 fatalities and 277 injuries.Facility/infrastructure attacks were the most frequently identified attack type (35.0%), followed by bombings and explosions (30.9%). Armed assaults were responsible for 80 fatalities and 105 injuries, followed by bombings/explosions with 15 fatalities and 72 injuries. The predominant target types were immigrants and refugee shelters (64/298 incidents). In only 33.6% of the incidents, perpetrators were known. Right-wing assailants represented the largest group, accounting for 27 incidents. CONCLUSION: From 1970 through 2020, there were 298 terrorist attacks in the Nordic-Baltic Eight. Sweden accounted for 50% of incidents.The profile of terrorist attacks was very diverse, as were the perpetrators and targets. Every country had its own incident characteristics. The surge of right-wing extremism must be closely monitored.

Similar crimes, similar behaviors? Comparing lone-actor terrorists and public mass murderers.

This article adds to the growth in data-driven analyses seeking to compare samples of violent extremists with other violent populations of interest. While lone-actor terrorists and public mass murderers are frequently treated as distinct offender types, both engage (or attempt to engage) in largely public and highly publicized acts of violence and often use similar weapons. This article investigates the (dis)similarities between both offender types. We use a series of bivariate and multivariate statistical analyses to compare demographic, psychologic and behavioral variables across 71 lone-actor terrorists and 115 public mass murderers. The results show little distinction in sociodemographic profiles, but significant differences in (a) the degree to which they interact with co-ideologues (b) antecedent event behaviors and (c) the degree to which they leak information before the attack. Overall, our data inform the emerging idea that lone-actor terrorists and public mass shooters are not distinct offender types. There is more that unites them than divides them. Although the over-arching focus of our results are on the few variables that distinguish them, the vast majority (80%+), of the 180+ variables showed no significant difference. We discuss implications for threat assessment and management in the context of these results.

A Decade of Terrorism in the United States and the Emergence of Counter-Terrorism Medicine.

BACKGROUND: The United States (US) is ranked 22nd on the Global Terrorism Index (2019), a scoring system of terrorist activities. While the global number of deaths from terrorism over the past five years is down, the number of countries affected by terrorism is growing and the health care repercussions remain significant. Counter-Terrorism Medicine (CTM) is rapidly emerging as a necessary sub-specialty, and this study aims to provide the epidemiological context over the past decade supporting this need by detailing the unique injury types responders are likely to encounter and setting the stage for the development of training programs utilizing these data. METHODS: The Global Terrorism Database (GTD) was searched for all attacks in the US from 2008-2018. Attacks met inclusion criteria if they fulfilled the three terrorism-related criteria as set by the GTD. Ambiguous events were excluded when there was uncertainty as to whether the incident met all of the criteria for inclusion in the GTD. The grey literature was reviewed, and each event was cross-matched with reputable international and national newspaper sources online to confirm or add details regarding weapon type used and, whenever available, details of victim and perpetrator fatalities and injuries. RESULTS: In total, 304 events were recorded during the period of study. Of the 304 events, 117 (38.5%) used incendiary-only weapons, 80 (26.3%) used firearms as their sole weapon, 55 (18.1%) used explosives, bombs, or dynamite (E/B/D), 23 (7.6%) were melee-only, six (2.0%) used vehicles-only, four (1.3%) were chemicals-only, two (0.7%) used sabotage equipment, two (0.7%) were listed as "others," and one (0.3%) used biological weapon. There was no recorded nuclear or radiological weapon use. In addition, 14 (4.6%) events used a mix of weapons. CONCLUSIONS: In the decade from 2008 through 2018, terrorist attacks on US soil used weapons with well-understood injury-causing modalities. A total of 217 fatal injuries (FI) and 660 non-fatal injuries (NFI) were sustained as a result of these events during that period.Incendiary weapons were the most commonly chosen methodology, followed by firearms and E/B/D attacks. Firearm events contributed to a disproportionality high fatality count while E/B/D events contributed to a disproportionally high NFI count.

Terrorism in the country of origin is linked to deterioration in the mental health of refugees.

Refugees flee their country of origin to escape threats to their existence. Yet, despite having left behind the immediate physical dangers in their country of origin, refugees may continue to experience negative psychological consequences of contemporary violence in that country because of their connection to it. Here, using longitudinal population data from Denmark, we show that refugees were substantially more likely to use antidepressants, and anxiolytic and hypnotic drugs in periods when their country of origin was more intensely afflicted by terrorism. The finding that contemporary terrorism in the home country is negatively associated with the mental health of refugees highlights the potential vulnerability of such groups and points to the need to identify the extended global consequences of terrorism.

Healthcare system impacts of the 2017 Manchester Arena bombing: evidence from a national trauma registry patient case series and hospital performance data.

INTRODUCTION: In response to detonation of an improvised explosive device at the Manchester Arena on 22 May 2017, we aimed to use detailed information about injured patients flowing through hospital healthcare to objectively evaluate the preplanned responses of a regional trauma care system and to show how routinely collected hospital performance data can be used to assess impact on regional healthcare. METHODS: Data about injury severity, management and outcome for patients presenting to hospitals were collated using England's major trauma registry for 30 days following hospital attendance. System-wide data about hospital performance were collated by National Health Service England's North West Utilisation Management Unit and presented as Shewhart charts from 15 April 2017 to 25 June 2017. RESULTS: Detailed information was obtained on 153 patients (109 adults and 44 children) who attended hospital emergency departments after the incident. Within 6 hours, a network of 11 regional trauma care hospitals received a total of 138 patients (90%). For the whole patient cohort, median Injury Severity Score (ISS) was 1 (IQR 1-10) and median New ISS (NISS) was 2 (IQR 1-14). For the 75 patients (49%) attending a major trauma centre, median ISS was 7.5 (IQR 1-14) and NISS was 10 (IQR 3-22). Limb and torso body regions predominated when injuries were classified as major life threatening (Abbreviated Injury Scale>3). Ninety-three patients (61%) required hospital admission following emergency department management, with 21 (14%) requiring emergency damage control surgery and 24 (16%) requiring critical care. Three fatalities occurred during early resuscitative treatment and 150 (98%) survived to day 30. The increased system-wide hospital admissions and care activity was linked to increases in regional hospital care capacity through cancellations of elective surgery and increased community care. Consequently, there were sustained system-wide hospital service improvements over the following weeks. CONCLUSIONS: The systematic collation of injured patient and healthcare system data has provided an objective evaluation of a regional major incident plan and provided insight into healthcare system resilience. Hospital patient care data indicated that a prerehearsed patient dispersal plan at incident scene was implemented effectively.

Terrorism in China and the Emerging Needs for Counter- Terrorism Medicine Following a Decade of Deaths and Injuries.

BACKGROUND: China is ranked 42nd on the Global Terrorism Index (2019), a scoring system of terrorist activities. While China has a relatively low terrorism risk, events globally have wide-ranging repercussions for future attacks, putting first responders and emergency health workers at risk. This study aims to provide the epidemiological context for the past decade detailing the unique injury types responders are likely to encounter and to develop training programs utilizing these data. METHODS: The Global Terrorism Database (GTD) was searched for all attacks in China between the years 2008-2018. Attacks met inclusion criteria if they fulfilled the terrorism-related criteria as set by the GTD's Codebook. Ambiguous events, as defined by the GTD's Codebook, were excluded. English language grey literature was searched to ensure no events meeting these criteria were missed. A focused search of online English language newspaper articles was also performed for any terrorist events between 2008-2018. RESULTS: One-hundred and eight terrorist events occurred in the study time period. Of the 108 incidents, forty-seven (43.5%) involved Explosives/Bombs/Dynamite (E/B/D) only, with an average fatality count of 2.9 and injury count of 7.5 per event. Twenty-seven (25.0%) used bladed or blunt weapons in melees with an average fatality count of 9.7 and an injury count of 8.8 per event. Five (4.6%) involved incendiary weapons with an average fatality count of 2.4 and an injury count of 7.2 per event. Two used only chemical weapons (1.8%) with no recorded deaths and an injury count of 27.0 per event. Two events had unknown weapon types (1.8%) with one recorded death and no injury count. One event used a firearm (0.9%) and led to one death and no injuries. One event used a vehicle (0.9%), which also led to one death and no recorded injuries. Twenty-three attacks used a mix of weapons (21.2%) with an average fatality count of 17.1 and an injury count of 12.0 per event. CONCLUSIONS: One-hundred and eight terrorist attacks were recorded between 2008-2018 on Chinese soil using well-understood modalities. This resulted in a total of 809 recorded fatalities with 956 non-fatal injuries. The most commonly chosen methodology was E/B/D, followed by melees and the use of bladed weapons. Three events individually recorded a combined casualty toll of over 100 people.

Terrorism in Australia: A Decade of Escalating Deaths and Injuries Supporting the Need for Counter-Terrorism Medicine.

BACKGROUND: Australia is ranked 71st on the Global Terrorism Index (GTI; 2019), a scoring system of terrorist activities. While it has a relatively low terrorist risk, events globally have wide-ranging repercussions putting first responders and emergency health workers at risk. Counter-Terrorism Medicine (CTM) is rapidly emerging as a sub-specialty needed to address these threats on the front line. This study aims to provide the epidemiological context for the past decade, detailing the unique injury types responders are likely to encounter, and to develop training programs utilizing these data. METHODS: The Global Terrorism Database (GTD) was searched for all attacks in Australia from the years 2009-2019. Attacks met inclusion criteria if they fulfilled the following terrorism-related criteria as set by the GTD. Ambiguous events were excluded when there was uncertainty as to whether the incident met all of the criteria for inclusion as a GTD terrorist incident. The grey literature was reviewed, and each event was cross-matched with reputable international and national newspaper sources online to confirm or add details regarding weapon type used, and whenever available, details of victim and perpetrator fatalities and injuries. RESULTS: Thirty-seven terrorist events occurred in the study time period. Of the thirty-seven incidents, twenty-six (70.2%) involved incendiary weapons, five (13.5%) involved firearms, four (10.8%) involved melee (bladed weapon/knife) attacks, two (5.4%) were explosive/bombing/dynamite attacks, and one (2.7%) was a mixed attack using both incendiary and melee weapons. All except one firearms-related incident (four out of five) resulted in either a fatality or injury or both. Every melee incident resulted in either a fatality or injury or both. CONCLUSIONS: In the decade from 2009 to 2019, terrorist attacks on Australian soil have been manageable, small-scale incidents with well-understood modalities. Eleven fatalities and fourteen injuries were sustained as a result of terrorist events during that period. Incendiary weapons were the most commonly chosen methodology, followed by firearms, bladed weapons, and explosive/bombings/dynamite attacks.

UK healthcare staff experiences and perceptions of a mass casualty terrorist incident response: a mixed-methods study.

INTRODUCTION: System learning from major incidents is a crucial element of improving preparedness for response to any future incidents. Sharing good practice and limitations stimulates further actions to improve preparedness and prevents duplicating mistakes. METHODS: This convergent parallel mixed methods study comprises data from responses to an online survey and individual interviews with healthcare staff who took part in the responses to three terrorist incidents in the UK in 2017 (Westminster Bridge attack, Manchester Arena Bombing and London Bridge attack) to understand limitations in the response and share good practices. RESULTS: The dedication of NHS staff, staff availability and effective team work were the most frequently mentioned enabling factors in the response. Effective coordination between teams and a functional major incident plan facilitated an effective response. Rapid access to blood products, by positioning the blood bank in the ED, treating children and parents together and sharing resources between trauma centres were recognised as very effective innovative practices. Recent health emergency preparedness exercises (HEPEs) were valued for preparing both Trusts and individual staff for the response. Challenges included communication between ambulance services and hospitals, difficulties with patient identification and tracking and managing the return to 'normal' work patterns post event. Lack of immediately available clinical protocols to deal with blast injuries was the most commonly mentioned clinical issue. The need for psychosocial support for responding and supporting staff was identified. DISCUSSION: Between-agencies communication and information sharing appear as the most common recurring problems in mass casualty incidents (MCIs). Recent HEPEs, which allowed teams, interdisciplinary groups, and different agencies to practice responding to similar simulated incidents, were important and informed actions during the real response. Immediate and delayed psychosocial support should be in place for healthcare staff responding to MCIs.

Polio in Afghanistan: The Current Situation amid COVID-19.

Polio is a deadly viral disease that has been paralyzing many children in Afghanistan. Despite fundamental efforts, primarily vaccination, to reduce the number of cases in Afghanistan, there are still many children who are deprived of the vaccine every year. Afghanistan is one of the two remaining countries endemic for polio, and the country has undergone various challenges that have hampered the eradication of this disease. The underlying challenges include inaccessibility of unsecured areas, illiteracy, refusal, and, most recently, COVID-19. The country is in the midst of a battle against COVID-19, and polio has almost entirely been neglected. Sadly, polio cases are increasing in the country, particularly in polio-free provinces. After an initial lockdown, many businesses have been allowed to resume, but the mass polio vaccination campaign has not restarted. New cases of polio will surge if endemic regions remain unvaccinated or inaccessible. To curb the further spread of polio, Afghanistan needs to resume nationwide house-to-house vaccination as restrictions due to COVID-19 are loosened.

UNIFIED: Understanding New Information from Emergency Departments Involved in the San Bernardino Terrorist Attack.

INTRODUCTION: Emergency departments (ED) are on the front line for treating victims of multi-casualty incidents. The primary objective of this study was to gather and detail the common experiences from those hospital-based health professionals directly involved in the response to the San Bernardino terrorism attack on December 2, 2015. Secondary objectives included gathering information on experiences participants found were best practices. METHODS: We undertook a qualitative study using Consolidated Criteria for Reporting Qualitative Research (COREQ) guidelines by performing semi-structured interviews with physicians, nurses, and incident management staff from multiple institutions responding to the San Bernardino terrorist attack. We coded transcripts using qualitative analysis techniques and we delineated and agreed upon a refined list with code definitions using a negotiated group process. Final themes were developed and analyzed. RESULTS: A total of 26 interviews were completed; 1172 excerpts were coded and categorized into 66 initial themes. Six final categories of communication, training, unexpected help, process bypassed, personal impact/emotions, and practical advice resulted. CONCLUSION: Our study provides context regarding the response of healthcare personnel from multiple institutions to a singular terrorist attack in the United States. It elucidates several themes to help other institutions prepare for similar events. Understanding these common experiences provides opportunity to prepare for future incidents and develop questions to study in future events.

[Psychiatric aspects of terrorism]. / Terrorismus aus psychiatrischer Sicht.

BACKGROUND: Terrorism belongs to the extreme forms of violence that have so far received little attention in psychiatric research and are rarely mentioned in textbooks of psychiatry. After terror attacks, however, the question regularly arises whether terrorists suffer from mental disorders. OBJECTIVE AND METHODS: The aim of this review is to summarize the multidimensional causes of terrorism with special emphasis on psychopathological aspects of the perpetrators. In addition to a brief summary of the historical background and recent developments in terrorism, a literature search was performed using PubMed, SCOPUS, PsychInfo and PsychARTICLES. RESULTS: From a psychiatric point of view, a differentiation between lone terrorists and group terrorists is essential. Lone terrorists have a much higher prevalence of psychiatric disorders, such as psychotic, paranoid and affective symptoms. The majority of terrorists acting in groups rarely suffer from such mental disorders. For these perpetrators biographic aspects and socialization, group dynamics and ideological personality profiles with narcissistic, histrionic, fanatic and antisocial components are more relevant. The phenomenon of terrorism predominantly being a male domain is discussed. CONCLUSION: The manifold manifestations of terrorism are caused by complex patterns of interacting biographic, sociological, ideological and psychopathological components that differ between lone acting and group terrorists. The real causes for acts of terrorism are not various ideologies permitting violence but consist more of a pre-existing violence-oriented mentality of the perpetrators looking for such ideologies to justify their acts. The possibilities of psychiatry in prevention and early recognition are limited. Some recently developed scales for risk assessment of extreme violence are mentioned.

Post-traumatic stress reactions and doctor-certified sick leave after a workplace terrorist attack: Norwegian cohort study.

OBJECTIVE: To explore the association between the psychosocial work environment and the risk of sick leave among governmental employees with symptom-defined post-traumatic stress disorder (PTSD) after a workplace bomb attack. DESIGN: A prospective study on employees who met the symptom criteria for PTSD. Questionnaire data on the psychosocial work environment 10 months after the terrorist attack was linked to registry data on doctor-certified sick leave in the period 12-22 months after the attack. SETTING: The bombing of the government ministries in Oslo, Norway, 22 July 2011. PARTICIPANTS: The study sample consists of 94 Norwegian governmental employees, all with symptom-defined PTSD from the Norwegian version of the PTSD checklist (Post-traumatic Stress Disorder Checklist-Specific) measured 10 months after the attack. RESULTS: After adjustment for sex and severity of PTSD symptoms, predictability at work reduced the odds of sick leave (adjusted OR=0.62, 95% CI 0.40 to 0.98). Sense of control over decisions at work was associated with fewer absence days for employees with sick leave (adjusted rate ratio=0.61, 95% CI 0.38 to 0.98). CONCLUSIONS: Employees with PTSD after workplace terrorism would benefit from control over their workplace conditions and increased predictability to reduce the risk of sick leave. The findings suggest that the work environment can facilitate employees' work ability after stressful events, independent of severity of PTSD symptoms.

The assassinations of investigative journalists Daphne Caruana Galizia and Veronica Guerin and the male-to-female birth ratio.

INTRODUCTION: Male live births are marginally more common than female ones. At a population level, this ratio (M/F) temporarily reduces in the months after major traumatic events. This study looks at whether the M/F live birth ratios in Malta and Ireland were affected by the assassinations of local investigative journalists Daphne Caruana Galizia (DCG) and Veronica Guerin (VG) respectively. METHODS: Data on monthly live births by gender in Malta and Ireland were gathered from the Maltese Public Health Directorate for Health Information and Research and the Irish Central Statistics Office online database respectively. M/F ratios at 3 to 5 months after the assassinations were compared to the monthly M/F ratio in the months preceding and following the events. In the case of DCG, the study period was from January 2017 to December 2018, while in the case of VG, it was taken to be from November 1995 to October 1997. RESULTS: In Malta, during the study period, there were 8914 live births (M/F 0.5139; 95% CI 0.514-0.524). There was a significant dip (χ2 = 5.1, p = 0.02) of the M/F ratio 4 months after DCG's assassination to 0.4529. This translates to an estimated loss of 21 male live births. In Ireland, during the study period, there were 102,368 live births (M/F = 0.5162; 95% CI 0.513-0.519). There was a significant dip (χ2 = 4.5, p = 0.03) of the M/F ratio 4 months after VG's assassination to 0.5. This translates to an estimated loss of 72 male live births. DISCUSSION: These findings add weight to the argument that national stressful events may be related to dips in the M/F ratio. Assassinations of journalists may have important population mental health implications.

Measuring media exposure to acute mass violence.

OBJECTIVE: Researchers have studied the influence of media exposure to acute mass violence (e.g., terror attack, mass shooting, etc.) on distress in populations not directly experiencing the trauma; however, the field has yet to achieve consensus on the measurement of media exposure. There has been a rapidly changing media environment since this body of research began, with the rise of social media. To address this, we developed a measure using the most relevant items from media exposure surveys and accounting for evolving social media. METHOD: We asked a sample of youth and adults (N = 1,249), ages 14 - 59 years old, about average time spent consuming news in general, time spent viewing coverage of specific terror attacks, and their emotional reactions to the media coverage. RESULTS: A confirmatory factor analysis specifying a 3-factor model was run on a subsample of the data (n = 308), and the data fit the model well, χ2(17) = 30.799, p < .05, root mean square error of approximation = .051 [90% confidence interval = .020, .080], comparative fit index = .989, and standardized root mean square error of approximation = .043. Measurement invariance was examined on the remainder of the participants (n = 937) to determine whether the model was invariant across participant sex. CONCLUSION: Analyses support that the factor structure of the measure was consistent across male and female participants. Implications on measuring media exposure to acute mass violence will be discussed. (PsycInfo Database Record (c) 2020 APA, all rights reserved).

Factors associated with PTSD and partial PTSD among first responders following the Paris terror attacks in November 2015.

During the evening of 13 November 2015, the deadliest terror attacks in France in recent times occurred in the Paris area. Overall, 130 people were killed, 643 were physically injured and several thousands were psychologically impacted. Thousands of first responders, including health professionals, firefighters, affiliated volunteers and police officers were mobilized that night and during the subsequent weeks. The aims of our study were to measure the psychological impact on first responders in terms of post-traumatic stress disorder (PTSD) and partial PTSD as well as associated factors 12 months after the 13 November 2015 terrorist attacks. First responders who had intervened during the night and/or the aftermath of the terror attacks had the possibility of answering a web-based study 8-12 months after the attacks. They satisfied criterion A of the DSM 5 definition of PTSD. PTSD and partial PTSD were measured using the PCL-5. Gender, age, educational level, exposure, first responder category, mental health and traumatic event history, training and social support were all analysed as potential factors associated with PTSD and partial PTSD, using multinomial logistic regression. Overall, 663 participants were included in this analysis. Prevalence of PTSD in our sample went from 3.4% among firefighters to 9.5% among police officers and prevalence of partial PTSD from 10.4% among health professionals to 23.2% among police officers. Low educational level and social isolation were associated with PTSD and partial PTSD. Intervention on unsecured crime scenes and lack of training were associated with PTSD. Special attention should be given to first responders living in social isolation, those with low educational levels and those who intervene in unsecured crime scenes. Education and training about the potential mental health consequences of mass trauma intervention should be developed.

Quantifying the dynamics of failure across science, startups and security.

Human achievements are often preceded by repeated attempts that fail, but little is known about the mechanisms that govern the dynamics of failure. Here, building on previous research relating to innovation1-7, human dynamics8-11 and learning12-17, we develop a simple one-parameter model that mimics how successful future attempts build on past efforts. Solving this model analytically suggests that a phase transition separates the dynamics of failure into regions of progression or stagnation and predicts that, near the critical threshold, agents who share similar characteristics and learning strategies may experience fundamentally different outcomes following failures. Above the critical point, agents exploit incremental refinements to systematically advance towards success, whereas below it, they explore disjoint opportunities without a pattern of improvement. The model makes several empirically testable predictions, demonstrating that those who eventually succeed and those who do not may initially appear similar, but can be characterized by fundamentally distinct failure dynamics in terms of the efficiency and quality associated with each subsequent attempt. We collected large-scale data from three disparate domains and traced repeated attempts by investigators to obtain National Institutes of Health (NIH) grants to fund their research, innovators to successfully exit their startup ventures, and terrorist organizations to claim casualties in violent attacks. We find broadly consistent empirical support across all three domains, which systematically verifies each prediction of our model. Together, our findings unveil detectable yet previously unknown early signals that enable us to identify failure dynamics that will lead to ultimate success or failure. Given the ubiquitous nature of failure and the paucity of quantitative approaches to understand it, these results represent an initial step towards the deeper understanding of the complex dynamics underlying failure.

Visualizing the relationship among indicators for lone actor terrorist attacks: Multidimensional scaling and the TRAP-18.

This validation study analyses data from a sample of North American terrorist attackers (n = 33) and non-attackers (n = 23) through the lens of the Terrorist Radicalization Assessment Protocol (TRAP-18; Meloy, 2017) utilizing a multivariate statistical approach - multidimensional scaling - to visualize potential clustering (co-occurrence) of risk factors. Rarely done in terrorism research, the results plotted in two-dimensional space show the clustering and co-occurrence of most of the eight proximal warning behaviors among the attackers, but not among the non-attackers, and less of a clustering and association of distal characteristics, but their presence in both attackers and non-attackers. These findings provide further empirical support for the rational-theoretical model of the TRAP-18, a structured professional judgment instrument for threat assessment of lone actor terrorists. It advances the quantitative analysis of operationally relevant and behaviorally observable indicators for use by law enforcement and counterterrorism professionals and their consultants. Findings are discussed in relation to other research on pre-offense behaviors of lone actor terrorists, and recommendations are made for both operational use and further research.