offender profiling- bottom up

The bottom-up approach to offender profiling aims to create a profile of an offender by analysing evidence collected from the crime scene. Unlike the top-down approach, it does not begin with fixed categories such as organised or disorganised offenders. Instead, investigators build the profile from the details of the offence itself. The approach is more data-driven and scientific, using statistical analysis and psychological research to identify patterns in offender behaviour.

One feature of the bottom-up approach is investigative psychology, developed by David Canter. Investigative psychology analyses patterns of behaviour displayed during crimes to identify characteristics of the offender. Canter argued that offenders display consistency in their behaviour, meaning the way they act during one crime is likely to reflect their behaviour in other situations. This is known as interpersonal coherence. Investigative psychology also uses smallest space analysis, a statistical technique that identifies patterns of behaviour across many crime scenes. Canter identified themes such as hostility, control and sexual behaviour in offender actions, which can help create a profile.

Another feature is geographical profiling. This involves analysing the locations of linked crimes to identify the likely operational base of the offender. Kim Rossmo developed the circle theory, suggesting offenders usually operate within a geographical area they are familiar with. Geographical profiling can help police predict where an offender may live or work by identifying patterns in crime locations. This helps narrow down suspects and focus investigations more efficiently.

One strength of the bottom-up approach is that it is based on scientific and objective methods. Investigative psychology uses statistical analysis and computer databases to identify patterns in offender behaviour, making the approach more evidence-based than the top-down approach. Research by Canter found evidence for behavioural consistency in offenders, supporting the assumptions of investigative psychology. This increases the reliability and scientific credibility of the bottom-up approach.

However, the bottom-up approach can be criticised because the evidence for behavioural consistency is mixed. Offenders may behave differently depending on the situation, the victim or emotional state at the time of the crime. This means behaviour may not always be stable enough to accurately predict offender characteristics. As a result, profiles created using investigative psychology may not always be reliable, reducing the validity of the approach.

A further limitation is that geographical profiling and investigative psychology are mainly useful for certain types of crimes, particularly serial offences such as murder, rape and arson. They are less effective for crimes committed impulsively or by offenders who do not show clear behavioural patterns. In addition, creating profiles requires large amounts of data and specialist analysis, making the approach time-consuming and expensive. Therefore, while the bottom-up approach can assist investigations, its usefulness may be limited in some cases.