The bottom-up approach

• The bottom-up approach to offender profiling is data-driven and aims to develop hypotheses about the likely characteristics, motivations and social background of the offender through statistical analysis rather than relying on pre-existing templates (like the top-down approach).

  • This approach was developed in the UK by David Canter and is more scientific and objective than the FBI’s top-down method.
• The bottom-up approach uses investigative psychology and geographical profiling.
• Investigative psychology is a form of the bottom-up approach that matches details from the crime scene with statistical analysis of typical offender behaviour patterns based on psychological theory.
• Features of Investigative Psychology

  • Applies statistical techniques to crime scene data to establish patterns of behaviour.
  • Looks at how offenders interact with victims and how their behaviour changes across crimes.
  • Includes concepts like interpersonal coherence (how an offender’s behaviour reflects their everyday personality).
• Geographical profiling is a form of the bottom-up approach that is based on the principle of spatial consistency: that an offender's operational base and possible future offences are revealed by the geographical location of their previous crimes.
• Features of Geographical Profiling

  • Developed by Canter and Larkin (1993).
  • Analyses the location of crimes to find patterns and predict where an offender is likely to live.
  • The Circle Theory suggests offenders tend to operate in a geographical area around their home base:
  • Marauders commit crimes close to home.
  • Commuters travel away from home to commit crimes.
• The assumption of geographical profiling is that serial offenders will restrict their 'work' to familiar areas, and so understanding the spatial patterns of their behaviour provides investigators with a 'centre of gravity' which is likely to include their home base (often in the middle of the spatial pattern).
• A strength of the bottom-up approach is that it uses scientific and statistical methods to analyse criminal behaviour. Unlike the top-down approach, which relies on intuition, bottom-up profiling is based on data analysis and probability. For example, Canter and Heritage (1990) conducted a content analysis of 66 sexual assault cases using smallest space analysis and identified common patterns of behaviour across offences. This suggests that investigative psychology is grounded in empirical evidence, making it more reliable and scientific.
• Another strength is that the bottom-up approach has been successfully applied to real-life investigations. For example, David Canter’s profile of the "Railway Rapist" (John Duffy) helped police narrow down suspects based on geographical profiling. This demonstrates that the method can have practical benefits in solving crimes. However, success stories are rare, and some argue that profiling is not always useful in catching offenders, limiting its overall effectiveness.
• A strength of geographical profiling is that research has found consistent patterns in offender locations, supporting the Circle Theory. Lundrigan and Canter (2001) analysed 120 US serial killer cases and found that the offenders’ home base was often located at the centre of their crime scenes. This suggests that criminals tend to operate in a familiar geographical area, supporting Canter's claim that spatial information is key in determining the base of an offender. This suggests that geographical profiling is a valuable tool in identifying offenders, particularly in serial crimes.
• A further issue is that the bottom-up approach is more useful for some crimes than others. For example, geographical profiling is most effective for crimes involving multiple offences, such as serial murders or rapes. However, for crimes like burglary or one-off murders, there may not be enough data to identify patterns. This means that while bottom-up profiling is a valuable investigative tool, it has limited applicability in certain cases.