This is the Final Summary Overview of a report on a study of terrorist temporal precursor patterns (behaviors prior to a major terrorist attack) across various types of terrorist offenders and varying organizational structures under which they operate.
The study focused on three major issues related to terrorists’ precursor behaviors: 1) a subgroup analysis of temporal, crime-specific patterns by group type; 2) the nature of the planning process; and 3) factors associated with the outcomes of terrorist incidents (success or failure). Researchers identified the most common precursor activities for a sample of 13 terrorism events in the United States. In this preliminary analysis, it was determined that precursor conduct occurred in a logical, rational sequence. Subsequent analysis concluded that types of behaviors were similarly distributed regardless of terrorist group type; for example, recruitment generally occurred early in the planning process, and the acquisition of weapons or explosive materials and meetings occurred in the latter stages; however, there was substantial behavioral variation by group type in the median number of days when these behaviors occurred. The length of the planning process also varied significantly in relation to the ideology of the terrorist group. This report outlines factors in a terrorist group associated with the volume of preparatory behaviors, the factors associated with the length of the planning cycle, and factors associated with the terrorist attack’s success or failure based on an analysis of 550 terrorist attacks. The study’s major findings cover terrorist group=specific patterns of preparatory activities, the nature of planning cycles and participation in terrorist preparations, and failures to execute successful attacks. 19 tables, 2 figures, and 11 references