Bottom-up approach

• What is the Bottom-up approach?

  This approach focuses on building up the small details to create a larger picture.

  • The method is data driven.
• What are the 5 aspects of the bottom-up approach?

  • Investigative psychology
  • Interpersonal coherence
  • Significance of time and place
  • Forensic awareness
  • Geographical profiling
• What is Investigative psychology?

  • Combines statistical evidence with psychological theory.
  • Databases are created containing information from crime scenes.
  • Any new offences can be put in the database and compared to see if there are similarities.
  • This can inform police if any crimes appear to be committed by the same offender.
• What is Interpersonal coherence?

  This states that the way a criminal acts at the crime scene or/with the victim may offer up some clues as to how they may behave in everyday situations
• What is Significance of time and place?

  • The location and timings of the crime may suggest where the offender lives.
  • Leads to geographical profiling.
• What is Forensic awareness?

  If criminals appear to "cover their tracks" it may suggest that either they have been in trouble before or have a job within the criminal justice system.
• What is Geographical profiling?

  • The study of spatial behaviour in relation to the crime and offenders.
  • Focuses on the location of the crime as clues to where offenders live, work or socialise.
• What is Canter's circle theory?

  The circle theory states that the offender is likely to live within the 'circle' of crimes committed
• What are the 2 ways that offenders can behave? (Canter & Larkin - 1993)

  The marauder: Who operates in close proximity to their home base.

  The commuter: Those who are likely to have travelled away from their home base.
• What is a strength of the bottom-up approach?

  Supporting evidence

  • Lundrigan and Canter collected details from 120 murder cases involving serial killers in the USA and examined using 'smallest space analysis'. Revealed spatial consistency in the behaviour of the killers. Supports Canter's claim that spatial information is a key factor is determining the base of an offender.
• What is a limitation of the bottom-up approach?

  Can lead to wrongful convictions

  • E.g., in the case of Rachael Nickell's murder, Coli Stagg was targeted as a likely suspect as he matched the profile.
  • However, new forensic evidence emerged leading to Robert Napper being convicted after he was originally ruled out of the enquiry. Illustrates that just because someone fits a profile, doesn't necessarily mean they are the offender.
• What is a strength of the bottom-up approach?

  Geographical profiling has support

  • Godwin and Canter (1997) found that 85 % of the offenders they studied lived inside the circle encompassing their offenses.
  • However, Koscis and Irwin found that only 50% of burglars lived in the circle defined by their offenses.