ABSTRACT
The risk of attack by terrorists is a major concern. Managing this risk was primarily the responsibility of federal law enforcement agencies before the September 11, 2001 (9/11) attacks changed perceptions about public vulnerabilities to terrorist attacks. Subsequently, concern about additional attacks have increased, expectations about developing effective counter-measures have become more urgent, and shortcomings in our understanding of the nature of the risks posed by terrorist and terrorist groups have become more visible. Indeed, one of the most troubling conclusions that emerged from scholarly reviews of the empirical literature on understanding the risks of terrorism was how little is actually known. There are excellent critiques of the terrorism literature that highlight several concerns (LaFree & Dugan 2004; Ross 1993; Silke 2001), but the use of limited and questionable data was clear (Hamm 2005; Ross 1993). Statistical analysis is rarely used in terrorism research (Merari 1991). For example, Silke’s (2001) review indicates that only 3 percent of articles in terrorism journals used inferential analysis compared to 86 percent in forensic psychology and 60 percent in criminology. Lum, Kennedy, and Sherley’s (2006: 8) important Campbell systematic review of over 14,000 terrorism articles published between 1971 and 2003, similarly found that only 3 percent were empirical.
