15%Percentage of least sophisticated attacks that involved six or more preparatory behaviors

56%Percentage of most sophisticated attacks that involved six or more preparatory behaviors

54%Percentage of incidents planned by a single individual that involved two or fewer percursor activities

52%Percentage of incidents planned by a group of four or more individuals that involved six or more precursor activities

Key findings on attack outcomes

  • As the level of sophistication of planned terrorist incidents increases, the likelihood that the incident will fail also increases.
  • The greater the number of terrorist precursor activities, the greater the probability that planned incidents end in failure.
  • Longer terrorist incident planning cycles increase the probability of incident failure.