Offender Profiling - The Bottom-Up Approach Flashcards
Describe the Bottom-Up Approach
● Based upon analysis of details of crimes previously committed.
● Using this data predictions are made about the profile of an offender who might
commit a specific crime or who might have a specific way of carrying out a crime.
What are the 3 main features developed by David Canter?
Interpersonal Coherence, Forensic Awareness and smallest space analysis
What is Interpersonal Coherence?
● People are consistent in their behaviour and therefore there will be links with elements of the crime and their everyday behaviour.
● People’s behaviour changes over time, and therefore looking at the differences in crimes
over a four-year period might offer further clues.
What is Forensic Awareness?
● Certain behaviours may reveal an awareness of particular police techniques and
past experience.
● E.g. Davies et al. (1997) found that rapists who conceal fingerprints often had a
previous conviction for burglary.
What is Smallest Space Analysis?
● This is a statistical technique developed by Canter.
● Data about many crime scenes and offender characteristics are correlated so that
Most common connections can be identified.
● For example, Salfati and Canter (1999) analysed the co-occurrence of 48 crime scene
and offender characteristics taken from 82 UK murder cases where the victim was a
stranger.
What are the 3 underlying themes identified?
Instrumental opportunistic = Instrumental’ refers to using murder to obtain something or
accomplish a goal; opportunistic’ means that the offender took
the easiest opportunities.
Instrumental Cognitive = a particular concern about being detected and therefore more
planned.
Expressive Impulsive = uncontrolled, in the heat of strong emotions, may feel provoked by victim.
What is Geographical Profiling?
Criminals may also reveal details about themselves through the locations they choose.
Geographical profiling analyses the locations of a connected series of crimes and considers
how this might relate to an offender’s place of residence.
What is the circle theory?
Canter and Larkin (1993) proposed that most offenders commit their crimes within a kind of imagined circle. They identified two types of offenders:
- Marauder - the offender’s home is within the geographical area in which crimes are
committed. - Commuter - the offender travels to another geographical area and commits crimes
within a defined space around which a circle can be drawn.
Whats criminal geographic targeting?
● This is a computerised system using a formula developed by Kim Rossmo.
● It produces a 3D map displaying spatial data related to time, distance and movement to
and from crime scenes.
● The map is called a jeopardy surface. Colours are used in the map to indicate likely
closeness to the crime scene.
A03 - Efficacy of the approach
● There are conflicting opinions about the usefulness of the Bottom-up Approach.
● Copson (1995) surveyed 48 UK police forces using investigative profiling and found that
over 75% of the police officers questioned said that profilers’ advice had been useful.
● However, only 3% said that the advice had helped identify the actual offender.
● This suggests that the method may not be that useful in actually catching offenders, but
the slight benefit that it affords could make it worthwhile in some difficult cases.
A03 - Marauder/Commuter Classification
● Using the Circle theory, it is evident that most offenders are identified as marauders,
which questions the usefulness of the “Marauder/Commuter Classification system.
● This is highlighted in a study by Canter and Larkin (1993). They studied 45 sexual
assaults showing a distinction between marauders and commuters. However, 91% of
the offenders were identified as marauders.
● Furthermore, Petherick (2006) pointed out that if a person’s home base is not actually at
the centre of the circle, this may mean that police may look in the wrong place.
● This means that the Circle theory/Bottom-up approach may be oversimplified.
A03 - Risks of the Approach
● Overall, the success rates for offender profiling and the views of police forces who have
used the techniques suggest that profiling can’t reliably identify an offender.
● However, profiling can assist police in narrowing down the field of possibilities.
● The big danger lies in sticking too closely to any one profile, as was the case in the
murder of Rachel Nickell. In 1992 the 21-year-old mother was stabbed to death. Forensic
psychologist Paul Britton helped the police to create a profile which led to the
identification of Colin Stagg.
● Later DNA evidence proved that Stagg was innocent and that the murder was actually
committed by Robert Napper demonstrating the danger of overreliance on profiling.
