Offender profiling: bottom up approach

• bottom-up approach


  A data-driven approach where statistical techniques are used to produce predictions about the likely characteristics of an offender.
• Statistical analysis


  Detect patterns of behaviour that are likely to occur across crime scenes - develop statistical database which acts as a baseline for comparison
• Interpersonal coherence


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


  Location of crimes used to infer home/operational base of offender
• Spatial consistency


  Criminals are likely to commit crimes in areas they are comfortable/familiar with
• Canter and Larkin's two models of offender behaviour

  Marauder + commuter
• marauder


  Operates in close proximity to their home base
• Commuter


  likely to have travelled a distance away from their usual residence
• Circle Theory (Canter and Larkin 1993)


  Pattern of offending locations are likely to form a circle around the offender's usual residence- can provide insight into nature of offence
• Strength - evidence supports investigative psychology

  Analysis on 66 sexual assault cases using smallest space analysis - several behaviours identified + each individual displayed a pattern - helps establish whether two or more offences committed by the same person - supports consistency in their behaviour
• Limitation- analysis database made up of solved crimes

  Likely to be straightforward to link together - suggests investigative psychology may tell us little about crimes that have few links
• Strength - evidence supports geographical profiling

  Researchers collated info from 120 murder cases in US - smallest space analysis revealed spatial consistency- leave home base but create circular effect especially marauders
• Limitation: geographical profiling may not be sufficient on its own

  Recording of a crime not always accurate + 75% of crime not reported- even if correct other factors matter - may not always lead to successful capture
• Extra - mixed results

  48 police departments surveyed- advice provided by profiler useful 83% of the time

  Same study revealed 3% of cases led to accurate identification

  Kocsis et al found chem students produced more accurate profiles than detectives

  May have little practical value when comes to solving cases