Standards and Definitions Related to Crime Patterns
Given this lack of a common language, before we go any further in discussing the identification of crime patterns, it is important to review standards and definitions as promulgated by the Standards, Methods, and Technology (SMT) Committee of the International Association of Crime Analysts (I AC A).
In 2011,1 АСА chartered the SMT Committee to begin to define “analytical methodologies, technologies, and core concepts relevant to the profession of crime analysis” (Gwinn, 2011, p. l).The resulting report, entitled Crime Pattern Definitions for Tactical Analysis (Gwinn, 2011), began to set standards not only for crime analysis definitions but also for procedures.The goals of the report, which was called a white paper, were to standardize the definition of a crime pattern, differentiate crime pattern types, and define and illustrate each of the different crime pattern types (Gwinn, 2011).
What Is a Crime Pattern?
According to the IACA report (Gwinn, 2011), a crime pattern is a group of two or more crimes reported to or discovered by police that are unique because they meet each of the following conditions:
- 1 They share at least one common factor; that common factor could be the type of crime; the behavior of the offenders or victims; the characteristics of the offender(s), victims, or targets; the property taken; or the locations of the occurrence of the offenses.
- 2 There is no known relationship between the victim(s) and the offender(s); this means that it is a stranger-on-stranger crime.
- 3 The shared common factor or factors make the set of crimes notable and distinct from other criminal activity occurring within the same general date range (say, a week or a month).
- 4 The criminal activity is typically of limited duration—ranging from a week or more to as long as a month or several months.
- 5 The set of related crimes is treated as one unit of analysis and is addressed through focused police efforts and tactics (Gwinn, 2011).
What a Crime Pattern Is Not
Again, according to the IACA report, a crime pattern is not a crime trend. A trend is a persistent, long-term rise or fall in temporally based data (Gwinn, 2011). Knowing about crime trends is valuable because it can alert the police and the community to increases or decreases in the amount of criminal offenses.
However, crime trend analysis does not examine shared similarities between specific crime incidents. For example, when a local police department reports that homicides in the city have increased by 14% over the past year, this is not reporting a crime pattern. Sometimes such reports give no information as to any common factors among the homicides, the victims, or the offenders. A crime pattern report would indicate commonalities. Therefore, a crime trend is not a crime pattern.
Also, a crime pattern is not a chronic problem. Ron Clarke and John Eck have defined a crime problem as “a recurring set of related harmful events in a community that members of the public expect the police to address” (Clarke and Eck, 2003, p. 7). Based on this definition, a crime pattern would technically be classified as a type of crime problem; however, it would differ from a crime problem in these important ways:
- 1 Scope and length: A crime problem is chronic in duration and persistent in frequency with occasional acute spikes; a crime pattern is short term and acute in frequency.
- 2 Nature of activity: A crime problem is related to “harmful events” that may include crime, safety, disorder, or quality of life concerns; on the other hand, a crime pattern is limited to a specific set of reported crimes.
- 3 Response: A crime problem requires specialized, strategic responses that often involve multiagency and community collaboration; a crime pattern usually requires routine operational tactics carried out primarily by the police agency responsible for that jurisdiction (Gwinn, 2011).
A crime pattern is not just defined by numbers and a summary report of crimes that are similar in some characteristics and occur in roughly the same location. Nor is a crime pattern simply a cluster of incidents on a map. A crime pattern is identified through a systematic, deductive analytical process, subsequently communicated to police agencies via some form of bulletin (Gwinn, 2011). The bulletin clearly and succinctly describes the critical elements of the pattern and highlights any notable implications for action. More specifically, crime pattern bulletins typically include analytical elements such as a geographic profile, a temporal profile, a list of potential suspects matching physical or MO descriptions, or other information that has value for an investigation or for a response seeking a solution.