Government organizations have put substantial effort into detecting and thwarting terrorist and insurgent attacks by observing suspicious behaviors of individuals at transportation checkpoints and elsewhere. This report reviews the scientific literature relating to observable, individual-level behavioral indicators that might-along with other information-help detect potential violent attacks. The report focuses on new or nontraditional technologies and methods, most of which exploit (1) data on communication patterns, (2) "pattern-of-life" data, and/or (3) data relating to body movement and physiological state. To help officials set priorities for special attention and investment, the report proposes an analytic framework for discussion and evaluation; it also urges investment in cost-effectiveness analysis and more vigorous, routine, and sustained efforts to measure real-world effectiveness of methods. One cross-cutting conclusion is that methods for behavioral observation are typically not reliable enough to stand alone; success in detection will depend on information fusion across types of behaviors and time. How to accomplish such fusion is understudied. Finally, because many aspects of using behavioral observations are highly controversial, both scientifically and because of privacy and civil-liberties concerns, the report sharpens the underlying perspectives and suggests ways to resolve some of the controversy while significantly mitigating problems that definitely exist.

"Prepared for the United States Navy"--T.p. "The research was conducted within the International Security and Defense Policy Center of the RAND National Defense Research Institute"--Title page verso.

Introduction. Background -- Scope -- Structure of approach -- Recurring themes -- Chapter structure / Developing intent. Motivational and emotional development -- Psychological convergence -- Recruitment or joining -- Summary activities and indicators / Planning and laying groundwork. Development of strategic priorities -- Target identification, intelligence, surveillance, and reconnaissance -- Materiel acquisition, testing, and development -- Development of CONOPs -- Training and mission rehearsal -- Long lead-time preparations -- Illustrative planning behavioral indicators / Immediate pre-execution. Psychological and physiological preparation for operation -- Changing patter or social interaction -- Ritual practices -- Deception and concealment -- Logistical preparation for operation / Execution and aftermath. Intelligence, surveillance, and reconnaissance -- Deployment and positioning -- Coordination and communication -- Target selection, shaping, and feints -- Main attack(s) -- Post-attack reporting and strategic communication -- Protective measures and adaptation -- Behavioral indicators of execution and aftermath / Technologies and methods. Detection and analysis of communication patterns -- Pattern-of-life data -- Data on movement and physiological state -- Distinctions helpful amidst controversy / Cross-cutting issues. Introduction -- Appropriate layering -- Sensitivity and selectivity -- Improving effectiveness with behavioral stimulation -- Dealing with countermeasures and adaptation -- Observation distance, covertness, and automaticity -- Combining information: from heuristics to information fusion -- Mitigating the consequences of false alarms -- Summing up / Conclusions. Continuing themes -- Observations -- Takeaways / Appendix A: methodological notes -- Appendix B: references and cases to support historic examples -- Appendix C: references and cases to support indicator tables -- Appendix D: information fusion methods.