Forensic psychology

14.1 · Free notes

Offender profiling: top-down approach and the FBI typologies

Key points

• Offender profiling is a behavioural investigative technique. It uses crime scene evidence to predict an offender's likely characteristics (such as age, occupation, relationships and lifestyle) so that police can narrow the suspect list.
• The top-down approach was developed by the FBI Behavioural Science Unit at Quantico, USA. It begins with a pre-existing typology and fits the crime scene evidence into it. It is deductive, in contrast with the data-driven bottom-up approach.
• The typologies came from Ressler, Burgess and Douglas (1986). They interviewed 36 convicted sexually motivated murderers and combined the interviews with crime scene and victim data.
• The FBI process has four stages: data assimilation (crime scene photos, pathology and victim background), crime scene classification (organised or disorganised), crime reconstruction (the sequence of events and the victim's behaviour) and profile generation (offender characteristics, motive and likely behaviour).
• The organised offender plans the crime and targets a stranger, often luring the victim. The scene is controlled and clean, the body is hidden, and the weapon and evidence are removed. The offender is typically of high intelligence, socially and sexually competent, in skilled work, living with a partner and following the case in the media.
• The disorganised offender acts spontaneously and attacks at random. The scene is messy, the body is left in view and the weapon is often left behind. The offender is typically of lower IQ, socially inadequate, in unskilled work, living alone near the scene and may have a history of mental disorder.
• A mixed category was later added for crime scenes that show both organised and disorganised features. This shows that the original dichotomy was too simple.
• Strength: the approach gives police a quick, structured framework for violent crimes such as serial murder and rape. In Copson's (1995) survey, 82% of police said profiles were operationally useful.
• Weakness (usefulness): in the same survey profiles were judged to have helped solve the case in only about 14% of cases, and led to the offender being identified in under 3%. Profiles are often vague and can fit many suspects (Barnum effect), so they are hard to falsify.
• Weakness (sample): the typologies were built from 36 American men using self-report interviews. The sample is small, unrepresentative and not generalisable to other crimes, cultures or female offenders. Self-report data may be unreliable.
• Weakness (validity): Canter et al. (2004) analysed 100 US serial murders with smallest space analysis. They found no distinct organised and disorganised subtypes. Many organised features were common to most offences, so the typology lacks empirical support.
• Weakness (situational factors): behaviour varies with the victim and the situation. The typologies assume offenders behave consistently, which ignores situational variation and personality. For AO3, compare with the bottom-up approach, which is more empirical.

In more detail

• Worked organised example: a victim is lured from a car park, the body is hidden and no weapon is found → organised offender, likely socially competent, employed and with a car.
• Worked disorganised example: a sudden attack near the offender's home with the weapon left at the scene → disorganised offender, likely living alone nearby and socially isolated.
• Testing the Barnum effect: Alison et al. (2003) found police officers rated a vague profile as accurate whether it was compared with the real offender or a made-up one.
• Best use: the FBI approach suits crimes with rich crime-scene information, such as murder and rape, rather than burglary or theft.