CPOST defines a suicide attack as an event in which one or more attackers deliberately kill themselves in an effort to harm or kill others.

Our definition avoids debates over the definition of terrorism by including all suicide attacks, regardless of political motivations.

The DSAT does not include Attempted Suicide Attacks, in which a perpetrator fails to kill him or herself, or Suicide Missions, in which the perpetrator may expect to be killed in an attack, but self-initiated death is not an essential part of the attack.

The DSAT does not record failed suicide attacks or suicide missions because they are not conceptually comparable to suicide attacks and are less consistently covered in media and other reports, making open source data unreliable at present for approximating the true number of failed attacks or suicide missions across the world.

CPOST codes suicide attacks based on the militant group’s intended target. We use primary sources such as claim texts issued by groups to determine the target of attacks. CPOST classifies target types in three broad categories:

• Civilian: “innocents” who neither govern, legislate, nor protect the country, also called non-combatants.
• Political: legislators, governors, mayors, councilmen, ministers, state administrators, etc. and their institutions and representatives.
• Security: the armed forces, police forces, armed militias, intelligence agencies, etc., including their facilities, employees, and support structures.

The DSAT includes a Status field to account for the accuracy of the attack data. CPOST separates all potential suicide attacks into two categories: Confirmed attacks and Possible attacks.

To be counted as a Confirmed Suicide Attack, the attack must be reported by two independent sources. These do not include two sources that gain information from the same newswires. For instance, if two sources both use a Reuters newswire as the basis of their report, the sources will not be considered independent. Militant groups' claims also serve as an independent source for attacks and generally provide insight into information surrounding individual attackers.

Possible Suicide Attacks fall into two categories: Too Few Sources (attacks with only one source) and Conflicting Reports (attacks where news sources conflict as to whether the attack was a suicide or not). CPOST researchers collect possible suicide attacks because information may become available in the future to confirm the attack. Our Data Collection Team periodically reviews possible attacks and if, upon review, new information confirms a possible attack as suicide, the attack status is changed in the database. The opposite is also true: if new evidence reveals that an attack no longer meets CPOST’s criteria for inclusion, it is removed.