What is Geographical Offender Profiling?
Geographical profiling is the study of criminal spatial behaviour, the development of decision support tools that incorporate research findings, studies of the effectiveness of these applications and exploration as to how such tools can help the police investigation. There are two fundamental approaches to geographic profiling (a) that individuals have a mental map of the areas and (b) route finding ability.
How Can Geographic Profiling Help the Police?
helps with prioritisation of offenders;
gives guidance on where to seek intelligence;
links crime to a common perpetrator;
predicts where the next crime is likely to take place; and
possibly links the geographical style to an offender.
Geographical Offender Profiling Map
1 Red = The Most Probable Search Area where the Offender's Home Will Be Found
2 Magenta = Second Most Probable Search Area where the Offender's Home Will Be Found
3 Green = Third Most Probable Search Area where the Offender's Home Will Be Found
4 Blue = Fourth Most Probable Search Area where the Offender's Home Will Be Found
5 Cyan = Fifth Most Probable Search Area where the Offender's Home Will Be Found
6 Yellow = Sixth Most Probable Search Area where the Offender's Home Will Be Found
7 Aqua = Seventh Most Probable Search Area where the Offender's Home Will Be Found
The relevant theories underlying geographic profiling, as they apply to offender profiling are now discussed.
Routine Activity Theory (Cohen & Felson, 1979).
‘Routine Activity Theory (R.A.T.)’ proposes that for a crime to occur there are three necessary components, which must converge in time and space:
the presence of a likely offender (an individual who is motivated to commit a crime);
a suitable target (e.g. something valuable and accessible); and
the absence of a capable guardian (e.g. security guard, policeman, citizen).
The movement of people throughout their daily routine activities generates such convergences, and thus influences the likelihood and risk of crime over time. The approach focuses on the discovery of “opportunities” in the form of victims and targets during non-criminal activities.
Crime Pattern Theory (Brantingham & Brantingham, 1981).
Brantingham & Brantingham drew heavily from R.A.T. to propose that individuals develop an awareness of space; an area of familiarity, during their day-to-day activities, and that this governs the geographic patterning of their criminal and non-criminal behaviour. Awareness spaces include nodes (the places that people travel to and from, e.g. home, work or friend’s house), paths (the routes between the nodes) and edges (the boundaries of the region of familiarity).
Rational Choice Theory (Cornish & Clarke, 1986)
Rational Choice Theory’ proposes that the decision to offend is purposeful and rational, and is made by weighing up the pros or gains (e.g. personal, financial) associated with a crime against the cons or costs (e.g. the risks involved). These decisions are governed by environmental cues, and the rational consideration of the efforts, rewards and costs associated with potential crime locations. Lundrigan & Canter (2001a) assert models of rational choice are concerned with offences such as burglary and robbery, which are instrumental. Lundrigan & Canter (2001a) also state that the rational choice explanation of spatial behaviour involves the making of decisions and choices which exhibit a trade-off between increased opportunity and greater reward the further an offender travels from home, as well as the cost of time and effort and risk. The benefits of a criminal action are the net rewards of crime and include not only material rewards but also intangible benefit such as emotional satisfaction. The costs or risks of crime are those associated with formal punishment should the offender be apprehended. Lundrigan & Canter (2001a) note the concept of limited rationality best explains spatial behaviour of offenders. Offenders do not consider all the relevant factors every time an offence is considered, other influences (moods, motives, perceptions of opportunity, alcohol, and their appetite for risk) apparently unconnected to the decision at hand take over. Offenders are, therefore, behaving rationally as they see at the time. What is considered rational may change over time.
Propinquity and Morphology
Canter, Hammond, Youngs, & Juszezak (2012) say there are two fundamental aspects of offenders’ geographical activities that allow inferences of their most likely home base or location to be inferred from mapping the locations of their offences. The first is propinquity, which is the tendency for the probability of the crime locations to reduce incrementally as the distance from the offender’s home/base increases, often depicted as an aggregate decay function. The other factor is morphology; this is the tendency for offences to be distributed around the offender’s home or base. Morphology relates to structure whereas propinquity relates to closeness. Propinquity deals with the proximity of crime locations to the main places in the offender’s life, notably his/her home, or base.
The Circle Hypothesis
The Circle Hypothesis builds on the idea of there being a simple starting point and to see if the offender would have a base within this area. It is not always clear how large the circle is, and it does not always follow that the offender has a base at the centre of the circle. However, the circle hypotheses is a predictor of the home location. Outliers have a significant impact on the size of the circle. The home base is typically where the individual sleeps, but this ultimately depends on the type of offender. Circle theory proposes that geographical profiling and individual offender profiling behaviour assumes that an offender’s home base will be central to their crimes.
Canter & Gregory (1994) found that individuals tend to offend close to locations in which they live. Offenders when travelling around their home area find places where crimes can be committed. Brantingham & Brantingham (1981) argue that the concentration of criminal activity around the home is influenced by biased information flows. More information will be available at locations close to the home base it is, therefore, more probable that offenders will be aware of criminal opportunities in these areas.
Brantingham & Brantingham (1981) contend that the security of the offender’s home range and the familiarity of the area outweighs the risk of recognition in regions that are not in the immediate area of the offender’s home base. Familiarity is thus a determining factor of where criminals will commit crimes. There are both maximum and minimum distances from an offender’s home/base to the area in which they offend. According to Canter & Gregory (1994), the literature supports the idea that a criminal forms a mental map of his home range. This mental map probably influences criminal and non-criminal spatial activity of offenders.
Criminals tend not to travel far to commit the first offence; a ‘buffer zone’ exists around the offender’s home where the offender is unlikely to engage in criminal acts because of the risk of identification (Brantingham & Brantingham,1981; Canter & Larkin,1993). Fritzon (2001) argues that the spatial behaviour of burglars is more random because essentially opportunity to commit burglary exists everywhere. The location of their crime site, therefore, might be expected to be more dependent on concerns about detection or opportunistic factors such as coming across a house which is unoccupied and does not present environmental or psychological obstacles against being burgled.
Canter and Larkin (1993) found that the home was a location within the crime circle and is likely to be close to the centre of that circle. The average distance of offences to home for offenders studied by Canter and Larkin (1993) was 1.53 miles. Criminals typically travel further away from home at some stages of their offending careers.
Canter and Larkin found that the diameter of the circle was the distance between the two furthermost crimes to define the area found in most the cases the offender lived in the area circumscribed by their crimes. The circle consists of the smallest area incorporating all the crimes. This research has been extended so that a prediction of the offender home location can be derived from any given series by:
defining the criminal range for that series using the smallest possible circle that encapsulates all the crime locations; and
treating the centre of that circle as the most probable location for the offender’s residence.
Marauders and commuters.
Commuters commit crime around an area that they have some familiarity with but this is well away from their home location. Marauders commit crimes that are more spread out. The assumptions underlying the marauderer model are:
the opportunity for crimes is evenly distributed;
the offender does have a base within the area of the crimes;
the tendency to put distance between adjacent offences;
offender feels vulnerable in the area of previous offences; and
no very precise targeting.
The Consistency Hypothesis.
The consistency hypothesis posits that criminals will carry out similar level crimes. They are more likely to live near the centre of the crime because they are more likely to know the area quite well and, therefore, there are more crimes committed in the area. The Spatial Consistency Hypothesis is that offenders will only commit an offence in an area that they know.
References and Recommendations for Further Reading
Bennell, C. Snook, B., Taylor, P. J., Corey., S. Keyton, J (2007) It’s no riddle choose the middle: effect of number of crimes and topographical detail on police officer predications of serial burglars’ home locations. Criminal Justice Behaviour. 34(1) 119 – 132
Bennett T., & Wright, R. (1984) Burglars on burglary: prevention and the offender. Aldershot, Hants: Gower
Block, R. & Bernasco,W. Finding a serial burglar’s home using distance decay and origin destination patterns: a test of empirical Bayes journey-to-crime estimation in the Hague. Journal of Investigative Psychology and Offender Profiling, 6(3) 187 – 211
Brantingham, P. J. and Brantingham, P. L (1981) Notes on the geometry of crime. In: Environmental Criminology, Edited by Brantingham P.J and Brantingham P. L. Beverley Hills: Sage; 27 - 54.
Canter, D. V. (1977) The Psychology of Place. London: Architectural Press.
Canter, D. V. (2007) Mapping murder: the secrets of geographical profiling. London: Virgin
Canter, D. V, & Gregory, A. (1994). Identifying the residential location of rapists. Journal of the Forensic Society, 34(3), 169-175. doi: 1016/S0015-7368(94) 72910-8
Canter, D. V. Hammond, L., Youngs, D. E, & Juszczak, P (2013). The efficacy of ideographic models for geographical offender profiling. Journal of Quantitative Criminology 29, 423 – 446.
Canter, D. V., & Larkin, P. (1993). The environmental range of serial rapists. Journal of Environmental Psychology, 13, 63– 69
Canter, D. V. & Youngs, D. E. (2009). Investigative Psychology: offender profiling and the analysis of criminal action. Chichester, John Wiley & Sons.
Cohen, L. E., & Felson, M. (1979) Social change and crime rate trends: A routine activity approach. American Sociological Review. 44(4) 588 – 608
Cornish, D. B., & Clarke, R. V. (1986). The Reasoning Criminal: rational choice perspectives on offending. New York: Springer
Fritzon, K. (2010). An examination of the relationship between distance travelled and motivational aspects of firesetting behaviour. Journal of Environmental Psychology, 21(1), 45 – 60 doi. 10.1006/jevp.2000.0197
Lundrigan, S., & Canter, D. V. (2001a). A multivariate analysis of serial murderer’s disposal site location choice. Journal of Environmental Psychology, 21, 423 – 432.
Lundrigan, S., & Canter, D. V. (2001b). Spatial patterns of serial murder: an analysis of disposal site location choice. Behavioural Sciences and the Law, 19, 595 – 610. doi:10.1002/bsl.431.
Paulsen, D. (2006). Human vs machine: a comparison of the accuracy of geographic profiling methods. Journal of Investigative Psychology and Offender Profiling. 3(2) 77 – 89
Snook, B. Canter, D. V., & Bennell, C (2002). Predicting the home location of serial offenders: a preliminary comparison of the accuracy of human judges with a geographic profiling system. Behavioural Sciences and the Law. 20, 109 – 118
Find Out More About Offender Profiling
- Offender Profiling
- Offender Profiling and Crime Analysis
- Offender Profiling a Review and Critique of Approaches