The bottom-up approach

Question 1

How does the bottom-up approach work?

Answer 1

Profilers work up from evidence collected from the crime scene to develop hypothesis about the likely characteristics, motivations and social backgrounds of the offender
Associated with David Canter, and is data-driven

Question 2

What are the three stages of the bottom-up approach?

Answer 2

1. Analysis of the crime scene
2. Psychological theory and statistical analysis
3. Creation of hypothesis of the probable characteristics of the offender

Question 3

Describe investigative psychology

Answer 3

The aim is to generate a picture of the offender’s characteristics, routines and background through analysis of evidence
Statistical procedures detect patterns of behaviour that are likely to occur (or coexist) across crime scenes
This creates a statistical ‘database’ which acts as a baseline for comparison
Specific crime details are matched against the database to see if a series of offences are likely to have been committed by the same person

Question 4

What are the two types of the bottom-up approach?

Answer 4

Investigative psychology and geographical profiling

Question 5

What kind of things do they look at in investigative psychology?

Answer 5

Interpersonal coherence (behaviour, interaction with victim eg. controlling or apologetic)

Significance of time and place (when the crime happened and where - offenders home?)

Criminal characteristics (placing them in categories)

Criminal career (how far into their criminal experience are they, pattern, how they might progress)

Forensic awareness (knowledge of the criminal justice system, previous subject of the police eg: covering tracks due to knowledge of evidence)

Question 6

Describe geographical profiling

Answer 6

The location of crime scenes are used to work out the likely home or operational base of an offender - ‘crime mapping’
Based on the principle of spatial consistency (people commit crimes within a limited geographical space)
Crime mapping is used to link local crime statistics, local transport and the geographical spread to make conclusions about the likely home or operational base, workplace and social hangouts of the offender

Question 7

What is the circle theory, linking to geographical profiling?

Answer 7

The idea that people operate within a limited spatial mind set that creates imagined boundaries in crimes are likely to be committed

The Marauder: the offender operates in close proximity to their home base

The Commuters: the offender is likely to have travelled a distance away from their usual residence

Question 8

What are 2 strengths for the bottom-up approach?

Answer 8

1. More objective and scientific than top-down approach
   It is more grounded in psychological theory and evidence, and less driven by speculation and hunches. Investigators are able to manipulate geographical, biographical and psychological data quickly to produce insights and results that aid investigations. The field of investigative psychology has expanded to include suspect interviewing and examination of the material presented in court.
   This suggests that the bottom-up approach is more systematic than the top-down approach and supports its utility in all aspects of the judicial process.
2. Evidence to support geographical profiling -
   Lundrigan and Canter (2001) collated information from 120 murder cases involving serial killers in the USA. Statistical analysis revealed spatial consistency in the behaviour of killers. The location of each body disposal site was in a different direction from the previous, creating a ‘centre of gravity’; the offender’s base was inevitably in the centre of the pattern. This effect was more noticeable for marauders.
   This supports Canter’s claim that spatial information is a key factor in determining the base of an offender and therefore the utility of the bottom-up approach.

Question 9

What are 2 limitations of the bottom-up approach?

Answer 9

1. Geographical profiling has its issues
   It cannot distinguish between multiple offenders in the same area, and also the method is limited to spatial behaviour (not any personality characteristics)
   As such, it is questionable as to how much more it offers than the traditional method of police placing pins on a map to see where a group of crimes were committed
2. Significant failures
   David Canter’s profile of the Railway Killer led to police interest in the method. Copson (1995) surveyed 48 UK police forces using investigative psychology and found that over 75% of the police officers questioned said that the profilers’ advice had been useful. However, only 3% said that the advice had helped to identify the offender.