Inductive Offender Profiling

Induction is about drawing general conclusions about the offender in an individual case based on patterns from previous crime cases. Statistical data, lawful patterns, and knowledge about groups of offenders are used to draw these conclusions. Deductive profiling has mainly been used for specific crimes such as serial murder and violent crime, while inductive profiling is used for many more categories of crime, such as burglary or theft.

Classifying crimes

In inductive offender profiling, recurring patterns are analyzed in previous crimes committed by convicted offenders. The aim is to identify different types of crime, for example based on which behaviors and details often occur together. Different characteristics of offenders are then linked to the different types of crime.

Inductive profiling of arsonists

To understand how inductive profiling can be used in criminal investigations, we can look at a study by Carter and Fritzon (1998), in which they analyzed arsonists.

First, a database was created of solved cases that met certain criteria, in this case arson. Each case was then coded based on different aspects. Researchers looked at, for example, the crime scene, whether the offender remained at the scene, and what consequences the fire had. The offenders were also coded based on characteristics such as age, level of education, and any substance abuse problems.

Statistical analysis was then used to identify patterns in the material, which made it possible to distinguish different types (clusters) of crime based on similarities in method.

Carter and Fritzon's study identified, among others, the following clusters:

• Expressive person: the act aims to gain attention, for example from family or authorities; often linked to self-harming behavior.
• Instrumental person: the act is directed at a specific person or institution, often as a form of revenge.
• Expressive object: the fire is directed at a place or building that has a special meaning to the offender.
• Instrumental object: the fire is more opportunistic and lacks personal symbolic value.

These crime types were then linked to characteristics of the offenders. The analysis showed the following regarding the offenders:

• The expressive person often suffers from mental ill health, such as depression or psychosis.
• The instrumental person more often has a lower level of education, substance abuse problems, and relationship difficulties.
• The expressive object type often occurs among people who have set fires before.
• The instrumental object type is often linked to younger offenders who have previously been in contact with the police or other authorities.

In summary, the inductive method relies on using statistics and previous cases to build profiles of offenders. A strength is that it rests on a large empirical foundation, which makes it more objective and less dependent on subjective interpretations. At the same time, a weakness can be that the profiles become relatively general and do not fully capture what is unique about individual cases.