The main variable categories presented in these data include: Identification Numbers, Incident Date, Incident Location, Incident Information, Attack Information, Target Information, Perpetrator Information, Perpetrator Statistics, Perpetrator Claim of Responsibility, Weapon Information, Casualty Information, Consequences, Hostage/Kidnapping Additional Information, and Source Information. Sub-variables under Identification Number include: Coder and Event ID. Sub-variables under Incident Date include: Year, Month, Day, Approximate Date, Extended Incident, and Date of Extended Incident Resolution. Sub-variables under Incident Location include: Country, Region, Province/Administrative Region/U.S. State, City, Vicinity, Location Description. Sub-variables under Incident Information include: Incident Summary, Criteria (Criterion 1: Political, Economic, Religious, or Social Goal, Criterion 2: Intention to Coerce, Intimidate or Publicize to Larger Audience(s), Criterion 3: Outside International Humanitarian Law), Doubt Terrorism Proper, Alternative Designation, Part of Multiple Incident, and Situation of Multi-Party Conflict. Sub-variables under Attack Information include: Successful Attack, Suicide Attack, Attack Type, Attack Type -- Alternative Categorization, Additional Attack Type, Second Attack Type, Second Attack Type -- Alternative Categorization, Third Attack Type, and Third Attack Type -- Alternative Categorization. Sub-variables for Target Information include: Target Type, Target Entity, Name of Entity, Specific Target, Nationality of Target, Additional Targets, Second Target Type, Second Target Entity, Second Name of Entity, Second Specific Target, Nationality of Second Target, Third Target Type, Third Target Entity, Third Name of Entity, Third Specific Target, and Nationality of Third Target. Sub-variables for Perpetrator Information include: Perpetrator Group Name, Perpetrator Individual Name(s), Perpetrator Group Type, Perpetrator Group Sub-Type, Group's Ideological Influences, Additional Perpetrator Group, Second Perpetrator Group Name, Second Perpetrator Group Type, Second Perpetrator Group Sub-Type, Second Group's Ideological Influences, Third Perpetrator Group Name, Third Perpetrator Group Type, Third Perpetrator Group Sub-Type, Third Group's Ideological Influences, Specific Motive, and Perpetrator Group(s) Suspected/Unconfirmed. Sub-variables for Perpetrator Statistics include: Number of Perpetrators, Number of Male Perpetrators, Number of Female Perpetrators, and Number of Perpetrators Captured. Sub-variables for Perpetrator Claim of Responsibility include: Claim of Responsibility, Mode for Claim of Responsibility, Claim Confirmed, Additional Claim of Responsibility, Second Group's Claim of Responsibility, Second Group's Mode for Claim of Responsibility, Second Group's Claim Confirmed, Third Group's Claim of Responsibility, Third Group's Mode for Claim of Responsibility, Third Group's Claim Confirmed, and Competing Claims of Responsibility. Sub-variables for Weapon Information include: Weapon Type, Weapon Sub-Type, Additional Weapons, Second Weapon Type, Second Weapon Sub-Type, Third Weapon Type, Third Weapon Sub-Type, and Weapon Details. Sub-variables for Casualty Information include: Total Number of Fatalities, Number of U.S. Fatalities, Number of Perpetrator Fatalities, Total Number of Injured, Number of U.S. Injured, and Number of Perpetrators Injured. Sub-variables for Consequences include: Psychosocial Consequences, Property Damage, Extent of Property Damage, Value of Property Damage, and Property Damage Comments. Sub-variables for Hostage/Kidnapping Additional Information include: Hostages/Kidnapped, Total Number of Kidnap Victims/Hostages, Number of U.S. Kidnap Victims/U.S. Hostages, Hours of Kidnapping/Hostage Incident, Days of Kidnapping/Hostage Incident, Country the Kidnapper/Hijackers Diverted To, Country of Kidnapping/Hijack Resolution, Ransom Demand, Total Ransom Amount Demanded, Ransom Amount Demanded from U.S. Sources, Total Ransom Amount Paid, Ransom Amount Paid by U.S. Sources, Ransom Notes, Kidnapping/Hostage Outcome, and Number Released/Escaped/Rescued. Sub-variables for Source Information include: Name of Source, Source Publication Date, Full Source Citation, Name of Second Source, Second Source Publication Date, Full Second Source Citation, Name of Third Source, Third Source Publication Date, Full Third Source Citation, and Prevailing Source.