Applications of Geographical Offender Profiling

Donna Youngs, David Canter, David Canter

• Editore: Routledge
• Anno: 2017
• ISBN:
  9781351957731
• Edizione: 1
• Argomento: Psychologie
• Categoria: Geschichte & Theorie in der Psychologie

Many law enforcement agencies are now analyzing where a crime is committed, to develop predictions on the offender, their location and other factors that could help with the investigation. Known as Geographical Offender Profiling (GOP), this approach relies on a combination of principles and methodologies drawn from many different disciplines, including psychology, geography, criminology and forensic science. This book brings together a cross-section of the major papers published in the field of GOP to explain the scope and application of GOP in different criminal contexts. For the first time some widely quoted but difficult to obtain 'classic' papers have been published together with an introduction that provides an up-to-the-minute context and an extensive bibliography of the most relevant publications in this burgeoning area of study.

PART 1
Empirical Bases

Chapter 1

Geographical Offender Profiling: Applications and Opportunities

David Canter and Donna Youngs

Geographical Offender Profiling as an investigative application was born out of the contributions a number of individuals showed they could make to police investigations (Canter 1994, Canter 2004, Kind 1999, Rossmo 1995) by providing some systematic analysis of where the perpetrator of a given offence was likely to live. These early forays rapidly gave rise to the development of a number of different Geographical Offender Profiling tools, generating considerable interest among police and other law enforcement analysts. Yet, of course, the effectiveness of any such tools arises from the breadth and validity of the empirical work on which they draw. Beyond this, the actual utility of Geographical Offender Profiling tools to police investigations is also dependent upon the way in which the tools are implemented and integrated with the investigative process. Contemporary investigative applications of Geographical Offender Profiling should emerge then not from the expertise of individuals but from integrated scientific activity, consisting of three distinct components (Canter and Youngs 2008):

a) Studies of criminal spatial behaviour – basic research

b) Development of decision support tools that incorporate research findings

c) Explorations of how such tools may help police investigations and the effectiveness of these applications

Key Findings on Criminal Spatial Activity

The emerging studies of criminal spatial activity over the last decade have revealed a number of consistent findings that add to the possibilities for the operational and strategic applications of offender profiling. It is useful to draw together some of these findings so that their details are available for consideration.

Home to Crime Distances

Rhodes and Conly [1981]¹ reported that offenders typically travelled less than three miles to carry out their crimes. Twenty years later with a new data set Costello and Wiles (2002) reported remarkably similar results. If we just consider burglary offences, as listed in Table 1.1, where the results from thirteen different studies, all in different locations are summarised, we can see a consistency in the average distance travelled from home to crime across many different places and time periods. The mean distances vary from 0.89 kilometres on the small island of Barbados to 3.87 kilometres in a small town in Southern England; all the other studies from many different places give mean distances between these extremes.

These distances are all calculated as the straightest line between the home and offence locations; ‘crow flight’ distances. There has been some discussion of whether the travel route would be a more appropriate way of calculating these distances, or even some route along a notional grid, as would be the case for many cities that have a network of roads either parallel or at right angles to each other, often known as a ‘Manhattan’ metric. However, as Phillips (1980) pointed out, the use of any sort of street distance is problematic because there is no guarantee that it reflects the actual route used by the offender and in any case there is a high correlation between street distances and straight line distances. Therefore, in general, researchers have used straight line distances such as those shown for burglary in Table 1.1.

For other types of crime there are different ranges of distances, but as Gabor and Gottheil [1984] report for Ottawa, quite different crimes such as sex offences, robbery or even auto theft are often carried out within the same overall range of distances that are found for burglary. The only crimes that typically appear to be carried out at much longer distances from home are serial murders and serial stranger rapes. Canter et al. [2000] report a mean of 46 kilometres for US serial killers, for example. Similarly, Warren et al. [1998] give a mean of 23 kilometres for US serial rapists.

There are still not enough detailed studies to unpack the processes that influence the distance offenders travel, or more particularly what special processes lead to the offenders travelling more than a few kilometres to carry out crimes. There are likely to be many factors involved. Targeting is one process (discussed in Canter and Youngs 2008); the degree of planning involved in the offence is like to be another [Fritzon 2001]. The density of opportunities for crime and the related density of guardianship will doubtless also prove to be influential on the distances offenders travel. Other social aspects of the crimes will need to be considered in addition. For example, if offenders carry out crimes together then it would be expected that their combined ‘mental map’ will be larger [Turner 1969].

The resources they have available beyond knowledge of places is another set of factors that will need to be considered. These relate to mode of transport [LeBeau 1987] and the amount of time a criminal can be away from a base without causing alarm or suspicion. Canter and Gregory [1994] propose that different resources will be available to different types of offenders. For example, younger offenders will travel shorter distances because they do not have access to vehicles and will be more likely to be missed if away from home for long periods of time. This hypothesis was supported by their findings that younger rapists did indeed travel shorter distances, reflecting the much earlier studies by Nichols (1980), Phillips (1980) and Baldwin and Bottoms (1976) that all show younger offenders do not travel as far as older ones. There may well be analogous processes that lead to criminals from ethnic minorities travelling shorter distances than others (Nichols 1980, Pettiway 1982), as Canter and Gregory [1994] show for rapists.

Table 1.1 Mean Distances (in kilometres) Burglars Travel to Offence Location

Study Author(s)	Location of Offences	When Offences Occurred	Type of Offence	Mean
White (1932)	Indianapolis, USA	1930	Burglary (N=121)	2.83
Rhodes & Conly (1981)	Columbia, USA	1974	Burglary (N=796)	2.61
Barker (2000)	Small towns in S. England	1981–1987	Burglary (N=30)	3.87
Snook (2004)	St. Johns (& surrounding areas), Canada	1989–1999	Burglary (N=41)	2.7
Wiles & Costello (2000)	Sheffield	1995	Domestic Burglary (N=1401)	3.02
	(Offender travel within Sheffield)	1995	Domestic Burglary (N=983)	2.94
	York	1995	Burglary	1.58
	Hambleton	1995	Burglary	2.70
	Sheffield	1995	Burglary	2.90
Dixon (2000)	Merseyside, UK	Unspecified	Residential Burglary (N=240)	2.84
Gittens (2004)	Parish of St. Michael, Barbados	1999–2005	Burglary (Residence) (N=43)	0.89
			Burglary (Business) (N=29)	1.48
Canter (2006)	Wandsworth, London	1998–2002	Burglary (Residential) (N= 825)	1.83

Variations across Types of Offence

The processes that give rise to differences in the distance travelled to offend may be regarded as having two sources of influence. One is aspects of the criminal and how s/he sets about committing the crimes. Impulsivity or planning are explored in Canter and Youngs (2008), as well as the resources of time, money and mode of transport. The other sources of influence are factors outside the individual’s direct control, most notably the opportunities for crime and related land use patterns.

Both of these aspects combine in the nature of the crime. Different crime types require different amounts and forms of planning on the part of the offender and may require him/her to have access to different kinds or quantities of resources. But the opportunities for different crimes will also be spatial distributed in different ways. It is therefore not surprising that a number of researchers have explored differences in the distances offenders travel for different types of crime.

Broadly, published studies tend to indicate that offenders travel further to commit property crimes, which presumably take more planning and more direct targeting of particular opportunities that may be widely distributed, than to commit crimes against the person, as Rhodes and Conly [1981] indicate. Van Koppen and Jansen, [1998] showed that within property crimes in Holland there is some indication that the greater the value of the property stolen, the greater the distance travelled. A quarter of a century earlier, in the USA, Capone and Nichols (1975) showed that the distance robbers travelled is directly related to the value of the property they steal. Again it may be hypothesised that this is because more extended searches or specific targeting is involved in stealing higher value goods. But, such findings are certainly not uniform, which is unsurprising as the opportunities for property crime vary considerably from one area to another. Such variations draw attention to the relevance of the contextual backdrop for the spatial patterns.

Longer distances may also reflect a more general commitment to the course of action. Such a process is suggested by Capone and Nichols’ (1975) report that armed robbers travel further than those who are not armed. Similar processes have been demonstrated within other types of offence. For example, Fritzon [2001] has shown that for arson, the more emotional offenses are committed at a shorter distance than those that have a very instrumental purpose. LeBeau’s (1987) finding that rapists travelled furthest if they were using a vehicle, a mean of 11.7 miles, is also interesting here. Given that Wiles and Costello (2000) showed that, at the general level, increased mobility did not lead directly to longer home to crime distances, LeBeau’s finding here may again be understandable in terms of levels of commitment.

The details of ex...