A consortium of researchers dedicated to improving the understanding of the human causes and consequences of terrorism

Research Brief: Validation of the Nationwide Suspicious Activity Reporting (SAR) Initiative


The Nationwide Suspicious Activity Reporting (SAR) Initiative (NSI) is a standardized process that includes stakeholder outreach, privacy protections, training, and facilitation of technology for the purpose of identifying and reporting terrorism-related suspicious activity in jurisdictions across the country. This study was undertaken to validate the NSI by comparing pre-incident activities of terrorists and violent criminal extremists in the United States to the 16 SAR categories or “SAR indicators” that are criminal in nature and those that require additional information or investigation before they can be determined to be criminal in nature:

  • Non-Criminal Activity/Further Investigation Required: Weapons Discovery; Materials Acquisition/Storage; Acquisition of Expertise; Observation/Surveillance; Recruiting; Photography; Eliciting Information; and Testing of Security.                                                                                                    
  • Criminal Activity/Terrorism Nexus: Expressed or Implied Threat; Sabotage/Tampering/Vandalism; Misrepresentation; Theft/Loss/Diversion; Breach/Attempted Intrusion; Cyberattack; and Aviation Activity.

Data on terrorism cases and associated SAR indicators come from the Extremist Crime Database (ECDB) and the American Terrorism Study (ATS), two open-source terrorism projects supported in part by START. A total of 351 cases were examined.  The cases ranged in date from 1972 to 2013.  Although most incidents occurred in the United States, several occurred abroad, and the ones in the United States were perpetrated by those having both domestic and international ideologies.

Publication Information

Full Citation:
Gruenewald, Jeff, and William S. Parkin, Brent L. Smith, Steven M. Chermak,Joshua D. Freilich, Paxton Roberts, Brent Klein.“Research Brief: Validation of the Nationwide Suspicious Activity Reporting (SAR) Initiative: Identifying Suspicious Activities from the Extremist Crime Database (ECDB) and the American Terrorism Study (ATS)." Report to the U. S. Department of Homeland Security. College Park, MD: START, 2015.