National Archive of Criminal Justice Data

This dataset is maintained and distributed by the National Archive of Criminal Justice Data (NACJD), the criminal justice archive within ICPSR. NACJD is primarily sponsored by three agencies within the U.S. Department of Justice: the Bureau of Justice Statistics, the National Institute of Justice, and the Office of Juvenile Justice and Delinquency Prevention.

Lone Wolf Terrorism in America: Using Knowledge of Radicalization Pathways to Forge Prevention Strategies, 1940-2013 (ICPSR 36107)

Principal Investigator(s): Hamm, Mark, Indiana State University; Spaaij, Ramon, Indiana State University

Summary:

These data are part of NACJD's Fast Track Release and are distributed as they were received from the data depositor. The files have been zipped by NACJD for release, but not checked or processed. Users should refer to the accompanying readme file for a brief description of the files available with this collection and consult the investigator(s) if further information is needed.

Typically, NACJD's Fast Track Release requires all direct identifiers to be removed or masked. As the sources of information for this collection are publicly available, direct identifiers were left within the collection.

This study created the largest and most comprehensive database ever created to date on lone wolf terrorism. It includes 1 Excel data file (LONEWOLF_NIJ_HAMM_SPAAIJ_2014_unlocked.xlsx; n=98, 23 variables). The information was gathered from an extensive review of previous research, biographies and memoirs, journalistic sources, government reports, court documents, encyclopedias and documentary films.

Qualitative interviews were conducted as part of this research, but these interviews were not made available for archiving.

Access Notes

  • These data are part of NACJD's Fast Track Release and are distributed as they were received from the data depositor. The files have been zipped by NACJD for release, but not checked or processed except for the removal of direct identifiers. Users should refer to the accompanying readme file for a brief description of the files available with this collection and consult the investigator(s) if further information is needed.

  • The public-use data files in this collection are available for access by the general public. Access does not require affiliation with an ICPSR member institution.

Dataset(s)

Dataset - Download All Files (1.044 MB)
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Study Description

Citation

Hamm, Mark, and Ramon Spaaij. Lone Wolf Terrorism in America: Using Knowledge of Radicalization Pathways to Forge Prevention Strategies, 1940-2013. ICPSR36107-v1. Ann Arbor, MI: Inter-university Consortium for Political and Social Research [distributor], 2017-11-16. https://doi.org/10.3886/ICPSR36107.v1

Persistent URL: https://doi.org/10.3886/ICPSR36107.v1

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  • RIS (generic format for RefWorks, EndNote, etc.)
  • EndNote XML (EndNote X4.0.1 or higher)

Funding

This study was funded by:

  • United States Department of Justice. Office of Justice Programs. National Institute of Justice (2012-ZA-BX-0001)

Scope of Study

Subject Terms:    criminal histories, mental disorders, political violence, radicalism, terrorism, terrorist profiles, terrorists

Smallest Geographic Unit:    None

Geographic Coverage:    United States

Time Period:   

  • 1940--2013

Date of Collection:   

  • 2013--2014

Unit of Observation:    Individual

Universe:    All known cases of lone wolf terrorism from 1940-2013 within the United States.

Data Type(s):    administrative records data

Data Collection Notes:

These data are part of NACJD's Fast Track Release and are distributed as they were received from the data depositor. The files have been zipped by NACJD for release, but not checked or processed. Users should refer to the accompanying readme file for a brief description of the files available with this collection and consult the investigator(s) if further information is needed.

Typically, NACJD's Fast Track Release requires all direct identifiers to be removed or masked. As the sources of information for this collection are publicly available, direct identifiers were left within the collection.

Qualitative interviews were conducted as part of this research, but these interviews were not made available for archiving.

Methodology

Study Purpose:    The purposes of this research were to create a database of lone wolf terrorism in America, along with a theory-informed case study component based on direct contact with incarcerated lone wolf terrorists, and a comparative analysis seeking to distinguish lone wolves from those who undergo radicalization in a group setting.

Study Design:   

Information on the 98 cases was gathered from an extensive review of previous research, biographies and memoirs, journalistic sources, government reports, court documents, encyclopedias and documentary films.

Researchers attempted to conduct in-depth personal interviews with seven inmates. Due to refusals and issues with informed consent, only one such interview was conducted. It was not made available for archiving.

Sample:   

To be included in the database and case studies, a case was required to meet the following definition: Lone wolf terrorism is political violence perpetrated by individuals who act alone; who do not belong to an organized terrorist group or network; who act without the direct influence of a leader or hierarchy; and whose tactics and methods are conceived and directed by the individual without any direct outside command or direction. Researchers discovered 98 cases fitting this definition between 1940 and 2013 - representing all known cases of American lone wolf terrorism for the period.

Of the 98 cases in the database, 38 cases occurred before the terrorist attacks of 9/11 and 60 took place after 9/11. Of the 60 lone wolf cases after 9/11, however, 15 cases were law enforcement sting operations involving confidential informants and undercover agents; hence, they do not qualify as authentic lone wolf cases since more than one individual was involved. The sting cases were nevertheless included in the database because stings against standalone extremists have become a major counterterrorism strategy since 9/11.

Time Method:    Cross-sectional

Weight:    None

Mode of Data Collection:    record abstracts

Data Source:

For a full list of sources, users should consult the accompanying documentation file.

Description of Variables:    The data file consists of 23 variables (n=98). All variables within this collection are qualitative. Variables include a case number, name, years active, attacks/plots, fatalities/injuries, weapons used, age at time of attack/plot, race/ethnicity, prior criminal history, social/political grievance, military history, employment status at time of attack/plot, psychological disorder, affinity with extremist groups, marital status, broadcasting intent, enabler of terrorism, locus of radicalization, triggering event, capture/arrest, popular culture influence, influences on popular culture, and sources of materials used by researchers.

Response Rates:    Not applicable

Presence of Common Scales:    None

Version(s)

Original ICPSR Release:   2017-11-16

Version History:

  • 2017-11-16 Updating codebook, documentation, and README files.

Utilities

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