ABSTRACT:This article provides an in-depth assessment of lone actor terrorists' attack planning and preparation. A codebook of 198 variables related to different aspects of pre-attack behavior is applied to a sample of 55 lone actor terrorists. Data were drawn from open-source materials and complemented where possible with primary sources. Most lone actors are not highly lethal or surreptitious attackers. They are generally poor at maintaining operational security, leak their motivations and capabilities in numerous ways, and generally do so months and even years before an attack. Moreover, the "loneness" thought to define this type of terrorism is generally absent; most lone actors uphold social ties that are crucial to their adoption and maintenance of the motivation and capability to commit terrorist violence. The results offer concrete input for those working to detect and prevent this form of terrorism and argue for a re-evaluation of the "lone actor" concept.

Research on terrorism has long been criticized for its inability to overcome enduring methodological issues. These include an overreliance on secondary sources and the associated literature review methodology, a scarcity of statistical analyses, a tendency for authors to work alone rather than collaborate with colleagues, and the large number of one-time contributors to the field. However, the reviews that have brought these issues to light describe the field as it developed until 2007. This article investigates to what extent these issues have endured in the 2007-2016 period by constructing a database on all of the articles published in nine leading journals on terrorism (N = 3442). The results show that the use of primary data has increased considerably and is continuing to do so. Scholars have also begun to adapt a wider variety of data-gathering techniques, greatly diminishing the overreliance on literature reviews that was noted from the 1980s through to the early 2000s. These positive changes should not obscure enduring issues. Despite improvements, most scholars continue to work alone and most authors are one-time contributors. Overall, however, the field of terrorism studies appears to have made considerable steps towards addressing long-standing issues.

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