AO3 Bottom-Up Approach

• +Supporting evidence. Canter and Heritage conducted an analysis of 66 sexual assault cases using smallest space analysis. Several behaviours were identified in most cases (e.g. using impersonal language). Each individual displayed a pattern of such behaviours, helps establish whether two or more offences were committed by the same person (case linkage). This supports one of the basic principles of investigative psychology (and the bottom-up approach) that people are consistent in their behaviour.
• -However, the database is made up of only solved crimes which are likely to be those that were straightforward to link together - a circular argument.

  This suggests that investigative psychology may tell us little about crimes that have few links between them and therefore remain unsolved.
• +Evidence to support geographical profiling. Lundrigan and Canter collected information from 120 murder cases in the

  US. Smallest space analysis revealed spatial consistency - a centre of gravity. Offenders leave home base in different directions when dumping a body but created a circular effect, especially in the case of marauders. This supports the view that geographical information can be used to identify an offender.
• -Geographical Profiling may not be sufficient in its own. Recording of crime is not always accurate, can vary between police forces and an estimated 75% of crimes are not even reported to police. Even if crime data is correct, other factors matter e.g. timing of the offence and age and experience of the offender (Ainsworth). This suggests that geographical information alone may not always lead to the successful capture of an offender.
• Mixed Results

  Copson surveyed 48 police departments and found that advice provided by a profiler was 'useful' in 83% of cases, which suggests the approach is valid. The same study revealed that only 3% of cases led to accurate identification. Kocsis found chemistry students produced more accurate profiles than detectives. This suggests that offender profiling may actually have little practical value when it comes to solving cases.