offender profiling: bottom-up approach

• bottom-up approach

  canter's bottom-up approach looks for consistencies in offender's behaviour during the crime - which can be inferred from the crime scene or from surviving victims. No initial assumption is made until a statistical analysis is used, using correlational techniques.
• investigative psychology


  an attempt to apply statistical procedure, alongside psychological theory to the analysis of crime scene evidence in order to establish patterns of behaviour that are likely to occur or co-exist across crime scenes - to develop a statistical database that acts as a baseline for comparison.

  This can allow specific details of an offence to be matched against this database to reveal important details about the offender and it may also determine whether a series of offences are likely to have been committed by the same person.
• geographical profiling 


  a form of bottom-up profiling 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 = crime mapping.
• the aim of bottom-up profiling


  to generate a picture of the offender - based on their likely characteristics, routine behaviour and social background, through systematic analysis of evidence at the crime scene.
• difference between top-down and bottom-up approach

  the bottom-up approach does not begin with fixed typologies - instead, it is data-driven and emerges as the investigator engages in deeper and more rigorous scrutiny of the details of the offence.
• what 3 factors does investigative psychology consider?

  1. interpersonal coherence
  2. forensic awareness
  3. smallest space analysis
• interpersonal coherence


  the belief that the way an offender behaves at the scene, including how they 'interact' with the victim, may reflect their behaviour in more everyday situations.
• forensic awareness


  describes those individuals who have been the subject of police interrogation before and their behaviour may show how mindful they are of 'covering their tracks.'
• smallest space analysis


  the main component for investigative psychology - statistical technique which uses police databases to create profiles by inputting the known information about a new crime into the database- the procedure will then look for patterns and consistencies in the new crime compared to previous crimes in the database.
• assumptions of geographical profiling


  serial offenders will restrict their work to geographical areas they are familiar with - so understanding the spatial pattern of their behaviour provides investigators with a 'centre of gravity' which is likely to include the offender's base (often in middle of spatial pattern.) It may also help investigators make educated guesses about where the offender will strike next = jeopardy surface.
• Canter's circle theory


  this theory presents the view that if you plot the points at which crimes have been committed, the criminal activity will fit within a circle - often around the usual residence, and can give insights into the nature of the attack. (e.g. whether it was planned or opportunistic, as well as revealing other important information about the offender.)
• 2 models of offender behaviour proposed by Canter's circle theory

  1. marauder - operates in close proximity to their home base.
  2. commuter - likely to have travelled a distance away from their usual residence.
• why did Canter carry out his study?


  he criticised the top-down approach and conducted research to test the reliability.
• aim of canter's study


  to test the reliability of the top-down typology by applying it to 100 cases.
• procedure of canter's study


  content analysis of 100 cases coming from published accounts of serial killers from the USA (cross-checked with court reports and officers where possible), using smallest space analysis.
• canter's findings


  twice as many disorganised crimes as organised crimes were identified, suggesting that disorganised offenders are easier to identify/more common.

  2 behaviours in the organised typology occurred a level significantly above chance - 70% cases the body was concealed, 75% cases sexual activity had occurred.

  Further analysis failed to reveal any significant differences between organised and disorganised variables.
• canter - conclusion


  canter concluded that instead of there being a distinction between the 2 types of serial killer, all of the crimes had an organised element to them. The distinction between serial killers may be a function of the different ways in which they exhibit disorganised aspects in their activities. It would be better to look at personality differences between offenders.
• core components of the bottom-up approach

  1. investigative psychology
  2. geographic profiling
• evaluation of bottom-up approach


  strength - scientific method

  weakness - relies on human input

  strength - widely applicable

  weakness - unreliable
• strength - scientific method


  relies on empirical evidence and objective analysis, setting it apart from subjective approaches that introduce bias - using statistical software allows researchers to analyse data without personal biases, revealing patterns that may go unnoticed = ensures consistent and replicable results, leading to more reliable data and accurate profiles - generates robust profiles that reflect the studied phenomena, enhancing the validity of findings, significantly improving the accuracy of profiling and fosters insights grounded in objective analysis.
• weakness - relies on human input


  reliability of many servers is reliant on precision of human input into servers, introducing a vulnerability to the potential for human error - risk manifests in various ways, including possibility of inaccuracies in data entry or failure to update existing records promptly = such lapses can diminish overall accuracy and validity of information stored within databases. Furthermore, many databases are limited to containing information on solved crimes - can skew perceptions and analyses of crime trends or patterns.
• strength - widely applicable

  investigative tool that can be applied to many cases, including burglary, murder, and arson - offers analysis based on behavioral patterns and characteristics of offenders, allowing enforcement to make accurate profiles.

  1. helps with identifying crime patterns in serial offenses that don't fit typical categories - analyzing where crimes happen and how they’re connected can predict future offenses and reveal hidden patterns =improves understanding of criminal behavior and helps police create better plans to catch offenders.
• weakness - unreliable


  Nickel case - rachels murderer was ruled out due to not fitting the profile (too tall) = it wasn't until they reopened the case that they realised Napper was actually the killer.

  Petherick stated flaws in circle theory - suggested that the assumption is that the base of operations is often in the middle, but this isn't always the case and can lead to time wasting = suggests that the data produced in geographical profiling is too simplistic.