CRIM 454 SFU Characteristics Associated with Crime Scene Behaviours Questions

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CRIM 454

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answer the discussion questions:

  1. Provide an example of a base rate fallacy.
  2. Which of the two approaches – statistical and clinical – you feel is the best for offender profiling? Are they incompatible?
  3. What are some of the characteristics that have been associated to crime scene behaviours?
  4. Considering the organized/disorganized model that we discussed last week, what are some of the potential problems associated with its use for profiling?


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Crim 454 Lecture 3 -Scientific Approaches to Crime Scene Profiling Misconceptions about profiling • • Misconception; 1. As a matter of routine profilers make predictions or assumptions about an offenders personality 2. The profilers role is to solve crime 3. Profiling as a whole I an established scientific endeavor Reality 1. Personality prediction has questionable validity and reliability. Statements about personality are often not helpful to investigators. Profilers should focus on behavioral indicators 2. Profilers provide information that may or may not be helpful to investigators. Profilers who are not law enforcement officers should not consider themselves an arm of law enforcement 3. Although scientific approach is recommended, profiling is in its early stage and is far from being established as a science Beginning of scientific crime scene profiling • • • • • Clinically based crime scene profiling; FBI behavioral science unit o This is where profiling as we know it today began Scientific crime scene profiling; David Canter in the UK -investigative psychology (IP) The railway killer (video) Main difference: IP is a statistical, research-based orientation Investigative psychology program (master and PHD) o Started at university of Surrey (UK) o 10 years later move to university of Liverpool o Now is at university of Huddersfield (UK) Questions for IP • • • • What are the important behavioral features of the crime that may help identify the offenders? What are the most appropriate ways of indicating the differences between crimes and between offenders? What inferences can be made about characteristics of the offender that can identify him or her? Are there any other crimes that are likely to have been committed by the same person? Personality paradox • • • Definition; o The readiness to invoke dispositions rather than explain behavior in terms of situational influences; an intuitive belief within most people that behavior is cross-situationally consistent vs much empirical evidence that suggests it is not The personality paradox is exemplified in the definition of profiling outlined below Profiling rests on the assumption that at least certain offenders have cinssitent behavioral traits. This consistency is thought to persist from crime to crime and also to affect various non-criminal aspects of their personality and lifestyle, thus making them, to some extent, identifiable Crim 454 Lecture 3 -Scientific Approaches to Crime Scene Profiling • • So what then? Theoretical framework that emphasizes the importance of person x situation interactions in generating behavior may provide a more productive model for offender profiling The A > C equation • • • A = all those actions that occurred in and are associated with a crime that are known to investigators before the offender is identified C = relevant and identifying characteristics of the offender Arrow represents = The scientific and logical processes that lead to inferences made about the offender, which will eventually lead to his or her arrest and conviction Potential error problems in profiling • • • • Heuristics o Mental shortcuts for dealing with information, making complex decisions, and drawing inferences in rapid and efficient manner Representative heuristic error o Generalization o Availability heuristic; ▪ The ease with which instances or associations come to mind Base rate fallacy o A decisions making error in which information about the occurrence of some common characteristic within a given population is ignored or not given much weight in decision making Expression of uncertainty o Statistical probabilities; based on empirical evidence concerning relative frequency (ex base rate) o Subjective probability judgements; based on profilers personal belief Ugal and Criminological Psycholog) (2000), 5, 23-46 © 2000 The British Psychological Society Printed in Creat Britain Offender profiling and criminal differentiation David Canter* University of Liverpool, UK Purpose. The psychological hypotheses that form the foundations for 'Offender Profiling' are identified and the research that has tested them is reviewed. Argument. 'Offender profiling' is taken to be the derivation of inferences about a criminal from aspects of the crime(s) he or she has committed. For this process to move beyond deduction based on personal opinion and anecdote to an empirically based science, a number of aspects of criminal activity need to be distinguished and examined. The notion of a hierarchy of criminal differentiation is introduced to highlight the need to search for consistencies and variations at many levels of that hierarchy. However, current research indicates that the key distinctions are those that differentiate, within classes of crime, between offences and between offenders. This also leads to the hypothesis of a circular ordering of criminal actions, analogous to the colour circle, a 'radex'. The radex model, tested using Multi-Dimensional Scaling (MDS) procedures, allows specific hypotheses to be developed about important constituents of criminal differentiation: Salience. MDS analyses reveal the importance of the frequency of criminal actions as the basis on which the significance of those actions can be established. Models of differentiation. The research reviewed mainly supports distinctions between criminals in terms of the forms of their transactions with their explicit or implicit victims. Consistency. Offenders have been shown to exhibit similar patterns of action on different occasions. The most reliable examples of this currendy are in studies of the spatial behaviour of criminals. Inference. Under limited conditions it is possible to show associations between the characteristics of offenders and the thematic focus of their crimes. In general these results provide support for models of thematic consistency that link the dominant themes in an offender's crimes to characteristic aspects of his or her lifestyle and offending history. Implications. Much of what passes for 'offender profiling' in practice and as reported in the factual and fictional media has no basis in empirical research. However, there are some prontising results emerging in some areas of study. These results are most likely to be of value to pohce investigations when incorporated into decision support systems and the training of police officers. The results do also provide new insights into the psychology of crime. »Requests for reprints should he addressed to David Canter, Centre for Investigative Psychology, Department of Psycholog)', Eleanor Rathhone Building, University of Liverpool, Liverpool L69 7ZA, UK (e-mail: 23 24 David Ganter When faced with a crime a police investigator has certain initial information on which to base decisions for the most appropriate way forward in order to identify and prosecute the culprit. The investigator's task is to draw conclusions from the information available about the crime that will faciUtate enquiries. The investigator may decide that more information is needed before any conclusions can be drawn, but a point will eventually come where inferences need to be made. These are inferences that aUow the association between the offender and the offence to be demonstrated. Often these inferences are of a direct kind: a fingerprint found at the crime scene can be linked to the fingerprint of a known individual in police records, or an eyewitness may recognize a person and send the poUce in search of the specified individual. However, there are many aspects of police investigations in which the inference process is much less straightforward. These are particularly problematic when the police have no Umited pool of suspects or no clear idea of where they should search to find such suspects. The challenge of a crime for which there is no obvious direction in which to look for the culprit have been at the core of crime fiction for nearly 200 years. The approach to facing this challenge was given archetypal form with the creation of Sherlock Holmes. With this creation the inference process was defined as the insightful deductions of a well-informed and briUiant mind. The model of expert deduction became synonymous with the Holmesian process of seeing links between particular clues and particular aspects of the perpetrator. This, of course, is a dramatized version of what poUce officers do on a day-to-day basis. As such it is an example of implicit person perception. Salient features of the crime are attended to in much the same way as people attend to salient features of a person with whom they come into contact. Then stereotypical cognitive models are drawn upon to make inferences about crime or the person that go beyond those particular saUent cues. In this context deduction is a form of impUcit reasoning in which whatever experience or logic the reasoner can draw upon will be used to derive inferences about the culprit from aspects of the crime. An example that illustrates this well is a case in which the victim of an unidentified assaUant noticed that the offender had short finger nails on his right hand and long nails on his left hand. Somebody with specialist knowledge suggested that this was a characteristic of people who are serious guitar players. It was therefore a reasonable deduction that the assailant was somebody who played the guitar. This example shows the fundamental weaknesses of the deductive approach. Without clear empirical evidence about the prevalence of this particular pattern of nail length it is difficult to know whether the claim that it is unique to guitar players is vaUd. It may not be true of many guitar players and it may be a pattern that exists in many other individuals. In fact, in the case in question, the offender who was eventually identified had no contact with guitars and had this pecuUar pattern of nail length because of his job in repairing old tyres. The collection of empirical evidence in order to support the inferences that may be made about the relationship between the crimes and the offender is the cornerstone of the inductive method of science. Indeed, it is a reasonable claim that the whole development of scientific psychology is essentially the introduction of an Profiling and differentiation 25 empirically based inductive approacb to deal witb issues tbat common sense bas dealt witb previously merely in terms of reasoning and otber forms of deductive opinion. It tberefore foUows tbat many of tbe inferences tbat are important to poUce investigators can be redefined as psychological questions open to empirical study. Psychologists as the original 'profilers' The mass media fascination with violent, sexually related crimes and criminals has encouraged the beUef tbat tbe study of tbe differences between criminals, and tbe making of inferences about their characteristics, is some unique area of expertise quite divorced from the main currents of contemporary psychology. The myth tbat is promulgated attempts to cbaracterize tbis process as originating solely from tbe speculations of US special agents of tbe Federal Bureau of Investigation (Ressler, Burgess, & Douglas, 1988). Tbese speculations bave been termed 'profiUng', or more fuUy 'offender profiUng', 'psycbological profiUng' or 'criminal personaUty profiUng'. Tbese terms bave taken on a quasi-mystical quaUty, witb even scbolarly autbors seeing the need to introduce discussions of 'profiling' with reference to fictional illustrations (e.g. Grubin, 1995; Ormerod, 1996). Perbaps one of tbe powers of tbe term 'profile' comes from tbe impUcation tbat it is a full and rounded picture of tbe unknown individual. Tbe term bas gained use in journaUsm as a distiUed account of everytbing tbat one needs to know about tbe person being profiled. But only a fictional creation could be a fuU pen-picture. Any scientific analysis wiU require a focus on tbe components tbat are significant and on wbicb tbere is a researcb Uterature. Some aspects of tbe account may be more weU estabUsbed tban otbers, so taking aU aspects of tbe account as being of equal merit is bound to be misleading. However, the inferring of general cbaracteristics of a person on tbe basis of a Umited amount of information about tbem bas scientific roots in psycbometric testing. Tbis was a Uvely brancb of psycbology long before the FBI was created. Furtbermore, as Delprino and Babn's (1988) survey of psycbological services in US poUce departments sbows, psycbologists were giving opinions to tbeir local poUce forces about tbe characteristics of criminals before the FBI 'Behavioral Science Unit' was estabUsbed. Tbis was a natural outgrowth of their major involvement in the development of predictive profiles of people applying for jobs in the poUce force. Tbis procedure, otberwise known as 'assessment of appUcants', as well as tbeir advice on cUnical matters relating to suspects sucb as fitness to plead and otber aspects of tbeir mental bealtb status, bas been an enduring psycbological contribution to tbe work of tbe poUce and tbe courts for some time. The study of individual differences and related examinations of personaUty may be summarized as 'What sorts of people carry out what sorts of actions?', the question at the heart of 'profiUng'. Studies of personal development and learmng strategies are also, in effect, examinations of the ways in wbicb people wbo differ, for example, in terms of development or experience also differ in terms of wbat they will do Lnd how they wiU do it. From this perspective, many attempts to derive 26 David Canter inferences about offenders' characteristics from the ways in which they commit their crimes can be seen as a subset of problems that is part of many broader questions in general psychology. Unfortunately, a number of popular writers have been unaware of the ways in which investigative inferences relate to questions in empirical inductive psychology. They have fostered the use of the term 'offender profiling' with the implicit and sometimes explicit implication that the process of profiling is something other than the application of psychology to a particular subset of applied problems. This confusion has been indicated by the many statements which refer to 'profiling' as a craft based on the particular expertise of the individuals who purvey it (Ressler et al., 1988). It has been aggravated by many claims for the possibilities of creating 'profiles' despite the remarkably limited amount of research which attempts to test out the possibilities for making valid inferences about a criminal from information relating to the crime that he or she commits. The frequently asked question of 'how accurate' or 'how useful' are 'offender profiles' (cf. Copson, 1995), therefore, are premature before there is any thorough test of clearly defined psychological bases for this process. Part of the reason for this confusion over the nature of 'profiling' and the unscientific haste with which the process has been promoted is that the popular origins of detective deduction is in the writings of crime fiction. This often confuses the process of psychological offender profiling with the actions of an expert detective. This confusion is understandable because the people who did most to promote the concept of offender profiling in its early days were law enforcement officers. These FBI agents, who were trainers at the FBI academy in Quantico, have presented models of the profiling process that rely very heavily on the particular personal perspective and expertise of the profiler (Ressler et al., 1998). This comparison between the deductive, 'fictional hero' approach and that of the empirical psychologist is not new to psychology. It is another example of the distinction between clinical and actuarial judgments that were explored by Meehl (1996). The clinician uses his or her judgments and experience to form an opinion about the patient in front of them. In contrast, actuarial judgments are those based on careful measurements and the resultant statistical relationships. In a series of studies first published in 1954 and followed up over the subsequent decades, it has been found that the actuarial decision processes were far more accurate and valid than those based on clinical judgment alone. Not surprisingly, the systematic scientific approach proved far more effective than that based upon personal opinion and judgment. This raises fundamental questions for psychological offender profiling. Is it possible to develop psychological measures of those aspects of criminal activity available to police investigators and of those characteristics of the offenders that are useful to help identify and prosecute those offenders? Can effective relationships between these measures be demonstrated? Limitations on sources and types of information Although the problem of inferring tbe characteristics of an offender from information available in the context of his or her crime is clearly a subset of the Profiling and differentiation 27 problems faced by psychologists in many other domains, it does have its own partictilar chaUenges and Umitations. It may be these particular problems and chaUenges that have led people to think that the process of offender profiUng is something different from developing inferences in conventional psychological contexts. The major Umitation is that the material on which the inference is based is restricted to that which is available during an investigation. This can be quite rich information, such as the detaUs of a rapist's sexual behaviour. It also includes such crucial factors as the time, place and nature of the victim, but it does not include the sorts of material that are the stock in trade of psychologists, such as the mental processes and personaUty characteristics as indicated in personaUty questionnaires. Neither is the material available coUected under the careful controls of laboratory research. It is therefore often incomplete, ambiguous and unreUable. SimUarly, in order for the inferences to be of value to investigators they must connect directly with things that poUce officers can actuaUy act on. Where an offender cotild be Uving is a clear example of useful information to an investigator, but more subde material such as how others may regard the offender or his or her Ukely skiUs and domestic circumstances may also be of value. Nonetheless intensive psychodynamic interpretations of the offender's motivations or other material, that might only become avaUable during in-depth therapeutic interviews, are less Ukely to be of direct assistance to poUce investigators. As in many crime novels the motivations, or possibly more accurately the reasons, why an offender carried out an offence can be of general interest to investigators, but they are only of value if they aUow inferences to be made that wiU faciUtate the detective decision-making process. Any quest for motivation or motive is best seen as an informal attempt to develop some explanatory model that wiU help to Unk the crime behaviour to the offender. So, for example, if the motive is thought to be monetary gain then someone who would have a need for such money or who recentiy seems to have acquired a lot of money would be assumed to be a viable suspect. However, without clear empirical evidence that the particular types of behaviour are associated withfinanciaUymotivated crimes and that these crimes are carried out by people with such need for financial gain, the interpretation of the motive and the inference drawn from it are Uttle more than speculation. The weakness of such speculation can be demonstrated by the finding that those who have carried out insurance fraud have not been in particularly straitened financial circumstances. Dodd (1998), for example, demonstrated that only 13% of the 209 fraudulent insurance claimants he examined were in financial difficulties, whereas 57% were earning a regular income. What are required scientificaUy are explanatory frameworks that can lead to hypotheses about the sorts of offender characteristics that are Ukely to relate to particular offence behaviour. There are very few studies at present which have demonstrated such relationships and even fewer theoretically precise models that provide guidance of where to search for such relationships. Rather, the stage has been reached at which the various constituents of such models are being explored and the tests of various components of general models are being carried out. The 28 David Canter remainder of this paper therefore reviews the more detailed empirical questions that are being explored and indicates the directions in which productive models may emerge in the future. Investigative problems The research questions that are covered by the inferences required for police investigations relate directly to a family of problems with which investigators are faced: (1) The salience of behaviours. What are the important behavioural features of the crime that may help identify the perpetrator? (2) Distinguishing between offenders. What are the most appropriate ways of indicating the differences between crimes and between offenders? (3) Inferring characteristics. What inferences can be made about the characteristics of the offender that may help identify him or her? (4) Linking offences. Are there any other crimes that are likely to have been committed by the same offender? All four questions are derivations of questions crucial to other areas of psychology. They involve concepts associated with the significant differences between one person and another and the features of one individual's behaviour that remain constant over different situations. It is therefore not surprising that many of the concepts and methods developed by psychologists over the last century, particularly in the field of personality and individual differences, have relevance for the study of crime. Areas of concern Psychological input can be valuable to the investigations of all crimes, not just those that catch the newspaper headlines like serial murder (Canter, Missen, & Hodge, 1996). As the scientific base grows it is also likely that the range of applications will grow. The original search for assistance from psychologists and others with some behavioural science knowledge was based on particular difficulties the crimes posed to investigators. The most notable was the idea that the crime had no obvious 'motive'. These 'motiveless' crimes were assumed to be driven by subtie psychological processes that required special expert insight. Taken together with the lack of any obvious relationship between the offender and the victim, these crimes were seen to pose very demanding challenges to investigators. However, motiveless, stranger crimes would seem to include many forms of casual vandalism (Canter, 1984), but it was serial killers that brought in 'profiling'. The reasons probably have more to do with the great public concern that stranger serial murders create and the consequent pressure on police to be seen to be using every available resource, than the special psychological basis of the criminal behaviour. For similar reasons, in many parts of the world those investigating all forms of serious stranger crime, including rape and murder, now regularly look for psychological input. Yet if such input is possible for these serious violent crimes why should it not be possible for all other crimes, including what are known as the 'mass crimes' of burglary and theft? In these crimes police investigators still need Profiling and differentiation 29 to Unk crimes to a common offender, often without the help of forensic evidence. They need to make inferences about offender cbaracteristics. Furtbermore, tbese questions need to be answered when only one crime is being examined, wbetber it is a serious crime or a mass crime. Tberefore, psychological assistance may be of value for 'one-off' crimes as weU as tbe serial crimes to wbich so mucb attention bas been paid in tbe mass media. Increasingly, also, it is becoming apparent tbat the questions of inference are relevant in a variety of other sorts of criminal investigations and poUce activities. For example, equivocal deaths, sucb as suspicious suicides (Canter, 1999), and ambiguous missing person investigations may benefit from psycbological support. Events tbat bave chaUenging bebavioural components sucb as bostage-taking and barricade siege may also yield to psycbological examination (WUson & Smitb, 1999). The anonymous threats and other questions relating to authorship also raise questions that are fundamentaUy psychological (Aked, Canter, Sanford, & Smith, 1999), although the crime scene is the actual written material rather tban a pbysical location. Organized crime and criminal networks take tbese psycbological questions into a distincdy social psycbological context. Tbe inferences and discriminations relate to teams, groups and networks not just to tbe individuals wbo make tbem up (Canter & Alison, 1999). Social psycbological researcb wiU consider tbe roles in tbe teams (Wilson & Donald, 1999) and nodes in networks (McAndrew, 1999), as weU as tbe characteristics associated with those roles (Johnston, 1999). A hierarchy of criminal actions The major premise for developing scientificaUy based profiUng systems is tbat tbere are some psychologicaUy important variations between crimes that relate to differences in the people who commit tbem. However, it is important to note tbat potentially tbere is a bierarcby of sucb possible distinctions. At tbe most general level there are questions about tbe differences between tbose wbo commit crimes and tbose wbo do not. Tbis is an area of study that has a long bistory in psycbology as Farrington's (1998) coUection of papers makes clear. At a mucb more specific level there are questions about particular subsets of activities tbat occur in a crime, say, wbether a particular type of weapon was used (Lobato, in press). Between tbe general questions and tbe particular is a continuum of variations tbat can be examined. Tbis would include questions about different subsets of crimes, sucb as the comparison of violent offenders and burglars (Farrington & Lambert, 1994). Or, at a sUghtly more specific level, questions about particular patterns of criminal behaviour, such as the comparison of offenders who prepare carefuUy in advance of a crime with those whose actions are impulsive and opportunistic. Figure 1 provides notional levels in this hierarchy. However, tbe Unear ordering of this table is an over-simpUfication. Offenders are not necessarily speciaUsts in one particular type of crime (Klein, 1984). This may mean that, for example, it is more vaUd to consider the difference between an offender who came prepared to carry out his or her crime and one who just grabbed what was avaUable, ratber tban 30 David Ganter Criminal versus non-criminal r Classes of crime (e.g. against property or person) \t Types of crime {e.g. arson, burglary, rape) J Patterns of criminal behaviour J Modus operandi f Criminal 'signature' Figure 1. A hierarchy for the difierendadon of offenders. focusing on differences in, say, whether it was a robbery or a burglary. In effect, this makes the description of crimes multi-dimensional. The notional hierarchy may be regarded as an inter-related set of dimensions for describing crimes. Such a complex structure is extremely difficult to examine in total. Researchers have therefore usually focused on one or other of the 'levels' of this hierarchy. For example, there are many studies examining the differences between offenders and non-offenders. There are fewer comparing the differences between those convicted of one crime and those convicted of another, and very few considering the differences between people who carry out similar crimes (e.g. rape) in different ways. The results of all these studies have relevance for 'profiling', although studies that aim to contribute to profiling tend to focus on the behavioural level. So far, no studies have been conducted to determine if the value and validity of inferences made on other dimensions are greater or less than those based on patterns of behaviour. The focus on patterns of behaviour in popular, anecdotal crime publications, as well as in the limited research literature, is in part owing to the many complications and unanswered questions within these multivariate issues. Some relate to the versatility of offenders. These raise questions of just what may be regarded as typical or characteristic of an offender. Other difficulties relate to the problem of defining tbe subgroup to which an offence should be assigned. Consider as an illustration a crime in which a house was burgled and at the same time a fire was set, giving rise to the death of an occupant. Would this crime be best tbought of as burglary, arson or murder? The charge made against the accused is usually for the Profiling and differentiation 31 most serious crime, but psychologically that may not be the most significant aspect of the offender's actions. One central research question, then, is to identify the bebaviourally important facets of offences, those facets that are of most use in revealing the salient psychological processes inherent in the offence. These carry great potential for answering questions posed by investigators. The radex model—beyond 'types' There is one particularly important implication of this multivariate hierarchy of criminal actions: the challenge it presents to the notion of a criminal 'type'. There are some aspects of a criminal's activities that are similar across many offenders. These lie at the most general end of the 'hierarchy'. They involve the actions that define the individual as criminal. But there will be other actions that the criminal engages in that are located further towards the specific end, the activities that identify a particular crime. Furthermore, some of the actions will overlap with those of other offenders, for example whether the criminal carries out his or her crimes on impulse or plans them carefully. Indeed, there will be relatively few aspects of ofTending, if any, tbat are unique to one given offender (these are often called, somewhat misleadingly, 'signature'). Even those may not be apparent in all the crimes that a person commits. The actions of any individual criminal may therefore be thought of as a subset of all the possible activities of all criminals. Some of this subset overlaps with the subsets of many other criminals, and some with relatively few. It therefore follows that assigning criminals or crimes to one of a limited number of 'types' will always be a gross oversimplification. It wiU also be highly problematic to determine what 'type' they belong to. If the general characteristics of criminals are used for assigning them to 'types', then most criminals will be very similar and there will be few types. But if more specific features are selected then the same criminals, regarded as similar by general criteria, will be regarded as different when considered in relation to more specific criteria. This is the same problem tbat personality psychologists have struggled with throughout this century. Their research led to the identification of underlying dimensions of personality. This 'dimensional' approach assumed that there were distinct, relatively independent, aspects of personality that could be identified. In recent years rather more complex models have emerged that do not require the simplifying assumption of independent linear dimensions (Plutchik & Conte, 1997). An analogy that helps in understanding this debate is the problem of classifying colours. Colours come in a virtually infinite variety, but in order to describe them some points of reference are necessary. These points of reference must cover the full spectrum of colours and they must be distinct enough for people to understand the reference. So, for instance, it would be unhelpful to try and discriminate colours merely on the basis of how much grey they contained and how much turquoise. Many differences between colours could not be accommodated in this scheme and many people may be unclear as to what colour grey or turquoise actually is. 32 David Canter Another approach may be classifying colours along dimensions of blueness, redness and greenness. Indeed many computer colour manipulation systems use just such a dimensional approach. These three hues do account for aU colours and they do have very clear meanings to people who are not colour bUnd. The psychological parallel of personaUty dimensions of extroversion and neuroticism, or in intelligence of spatial, numerical and verbal ability, also seeks to describe people in their combined position along all the identified dimensions. As with colour naming, a great deal of research has gone into determining what the major dimensions of personaUty or intelUgence are and of specifying how they may be measured as clearly as possible. But even though the dimensional classification scheme can be very productive it does have a number of Umitations. This can be Ulustrated by considering yellow in the above colour example. Most people regard this as a distinctly different colour from red, blue or green. Yet the computer, say, only gives one of these three dimensions to use. How can yellow be produced? It takes special knowledge of the system and how colour combinations work to realize that red and green will generate yeUow. The reason why this difficulty arises is that colours are not perceived along distinct dimensions, but rather as blending into each other. Various oranges sit between red and yellow, browns between yellow and green, turquoises between green and blue, purples between blue and red, and so on. Indeed for some purposes, such as printing, it is more useful to think of the 'between' colours, or 'secondary colours' as they are known, as the defining dimensions (i.e. cyan, magenta and yellow). This switch from one set of axes to another is only feasible because they aU merge into each other in a continuous colour circle (as pointed out by the artist Albert Munsell, 1960). The existence of a circle of colours does not deny the value of defining the major points of this circle. But rather than treat them as independent dimensions they are dealt with as emphases from which other combinations can be readily derived. The parallels with criminal actions are very strong. In order to describe those actions one needs to identify the dominant themes, but it would be unproductive to regard these themes as independent dimensions. It would be even more misleading to regard them as pure types, just as it would be misleading to think that colours can only be pure red, green or blue. The hierarchy of criminal actions also lends support to a circular ordering of criminal actions as a parallel with the colour circle. At the centre of the colour circle are those aspects of colour that all colours share—the degree of greyness. It depends on whether lights or pigments are being considered, but for simpUcity it is just necessary to remember that Isaac Newton showed that white light contained all the colours. So if all lights of all colours are combined they produce white. This is the centre of the colour circle. As the colours move out from this central position they become more specific and more distinctly one colour or another. The same mathematical process can be hypothesized for criminal behaviour. At the centre, are actions typical of aU the criminals being considered. These are the general aspects of the sorts of crimes that are the particular focus. As the actions become more specific to particular styles of offending so they would be expected to be conceptually further from the 'centre' of general criminality and thus more differentiating between criminals. Profiling and differentiation 33 It can thus be appreciated that this hypothesized model of the variations between criminals has two facets to it. One is the facet of specificity, moving from the general, shared by all offences and therefore conceptually in the middle, to the specific at the periphery. The other is the thematic facet that distinguishes between the different qualities of the offences, conceptually radiating around the 'core'. This model was recognized by Guttman (1954) as a powerful summary of many forms of differentiation between people and named a 'radex'. This is the hypothesized model that a number of researchers are testing in taking the first step towards answering the psychological and investigative questions introduced above. The crucial discovery in testing such a hypothesis is the identification of the dominant themes that can be used to classify any set of crimes. In the process it is often possible to give more substance to tbe meaning of specificity in that criminal context. In other words, the research may allow a determination of what the aspects of crime are that reveal the differences in the thematic emphases. For example, is it the degree of planning, or the forms of contact with the victim, or the intensity and legal seriousness of the actions, or some other underlying aspect of the crime, that produces the mixture of salient variations between crimes? A number of different researchers have explored these possibilities in a variety of ways. Not all of them follow through the details of the radex hypothesis, either because of the weaknesses of the data they have available or the current impoverished levels of conceptualizations of criminal actions. But a growing number of studies are finding the radex model to be a powerful conceptual tool for differentiating criminals (Canter & Alison, 2000). MDS analysis as a test of aspects of the radex hypothesis The quest to find the underlying themes that will be most productive in answering investigative questions and helping determine the characteristics of offenders can be conducted in many different ways. But many researchers do find it fruitful to use an approach that relies heavily on what is known as non-metric multi-dimensional scaling (MDS) (Canter, 1983; Shye & Elizur, 1994). It is worth emphasizing that this is not the only procedure available and that every procedure has its own strengths and weaknesses. Doubtiess as research develops in this area other procedures and approaches will be explored and a productive debate on which is most worthwhile will ensue. However, MDS, and especially its non-metric forms, clearly has much to offer this field. MDS procedures in general and the particular ones utilized in much profiling research have a long and very wide history of use in psychology, the related social sciences and other areas of the biological sciences (Borg & Shye, 1995). They have been used for everything from the classification of cetácea (whales) to the examination of neonatal heart defects; from the study of the genetic basis of behavioural differences in mice to reasons for taking up dieting; and from the effects of drug addiction in parents on their children to architects' development of the concepts of style. (Full reviews of the approach and details of these studies are given in Canter (1985) and Levy (1995).) 34 David Ganter In essence, the procedures consist of calculating the correlations between a set of variables and then representing these correlations as proximities in a notional 'space'. This has the great advantage of being able to examine each of the variables in relation to every other as part of one general visual pattern. The consideration of the facets that differentiate the actions of offenders (discussed above by analogy with the colour circle) requires the examination of the way every action relates to every other in some notional space. MDS procedures therefore allow direct test of the radex hypothesis and simplifications of that hypothesis. To carry out these tests the correlations between the actions need to be established. Often the best that can be hoped for, given the crudeness of the data, is that the co-occurrence of actions across a range of crimes can be examined. These co-occurrences are taken as the basis for measure of association between the variables, and association coefficients that only take account of occurrences and ignore non-occurrences are often used Qaccard, 1908). Another aspect of the approach that has been emphasized is that it is the dominant themes among these variables that are important. In other words, it is the relative distinctions between one set of actions and another that is important, rather than where they may sit on some absolute values of an underlying continuum. It is the relative associations between actions that is represented. To illustrate from the colour analogy, it may be the case that all the colours in a sample have a bluish tinge to them because of faults in the process used to reproduce them. A technique that would produce the colour circle would be helpful, not one that was greatly biased to show the results as merely aspects of blue. The preferred MDS procedures are thus ones that represent the rank order of the associations as rank orders of the proximities in the notional space. It is this representation of the relative degrees of associations, through ranks, rather than the absolute or 'metric' values, that gives the procedures the label of 'non-metric' MDS. This is an important technicality. It greatly facilitates the interpretation of what is often less than clear data. Behavioural salience One way in which MDS analyses have proven productive is in the examination of the fundamental question of salience in a pattern of criminal behaviour. There are many things that occur in a crime. Therefore, the challenge to the police officer, as for the researcher, is to identify those features that are of most relevance to deriving inferences about the offender. The determination of the salient characteristics is an empirical question in the sense that some knowledge of the base rate of behaviours of particular classes of crime is essential before the characteristics that are particularly important in understanding a given offence can be appreciated. The utilization of MDS leads to the hypothesis that the hierarchy of criminal differentiation illustrated in Fig. 1 should have an empirical correspondence in the radex structure illustrated in Fig. 2. The more general aspects of a crime typical of all criminals are hypothesized to be at the centre of the radex with the signatures at the periphery, as shown in Fig. 3. The model of behavioural salience is a refutable hypothesis because it is possible that distinct subgroups of actions could occur in any class of crime which, whilst Profiling and differentiation 35 -ThemeAparticular Theme F Theme B 'Theme DFigure 2. A general model for a radex as applied to the actions of criminals. ..-Theme A Signature Modus Operandi Theme F ' Theme DFigure 3. Representation of behavioural salience in a radex of criminal behaviour. frequent, were typically associated with distinct sets of rarer actions. In such a case the concentric circles that make up the radex would not be found. In this framework degree of salience is the location of an action at different distances from the centroid of the pattern of actions revealed in the MDS analysis. The first published study to demonstrate the existence of such a radial structure for crime was Canter and Heritage's (1990) study of rape. But a more recent study by Canter, Hughes, and Kirby (1998) of paedophilia also serves to illustrate the 36 David Canter power of the radex model in helping to indicate the salient aspects of a crime. For although in their study the three activities of 'initial force used by offender', 'the offender was recorded to have carried out the offence only once' and 'the offender tried to desensitize the victim to the offence', all of which occurred in about 40% of the 97 cases they studied, the distribution in the MDS plot shows that they tended to occur in very different crimes. Furthermore, they co-occurred with rather different sorts of other actions. For example, initial force was related to a number of other less frequent violent actions carried out by the offender, whereas desensitization tended to co-occur with rarer actions that impUed attempts to develop an intimate relationship with the child victim. In a number of studies saUence has emerged as related to the social psychological context of the offence rather than the focal actions that define the offence. In Canter and Heritage's (1990) study they report that 'the use of the woman as a sexual object is at the core of sexual assault' (p. 198). The saUent differentiations, therefore, are those that relate to how this core activity is instantiated in any particular offence. In their study of arson, Canter and Fritzon (1998) used Shye's (1985) action systems model to give a more precise definition of the variations in modes of criminal activity that provide the key to understanding differentiation. They demonstrate that differences 'relate to the source of the action and the locus of its desired effects' (p. 80). This concern with source and locus of the intended effects of crime follows the discussions of the role of emotion in offending that can be traced back to the consideration of instrumental aggression in violent crimes (e.g. Buss, 1961; Fesbach, 1964). Canter and Fritzon (1998) generaUzed the consideration of whether violent crimes were instrumental or expressive to cover other forms of crime, notably arson. They did this by regarding crimes as aimed at a variety of types of targets. Sometimes the target may be a modification of the criminal's feeUngs, and thus essentiaUy expressive, or they may be a search for a particular overt reward, thereby being essentially instrumental. It is this overlay, or elaboration, of the central criminal acts that give those acts their significance and investigative saUence. The elaboration is clearest when the acts can be seen in the general context of other actions committed during similar crimes. If they can be modelled in relation to the overall frequency of actions that occur in that class of crimes then a reasonably precise definition of their saUence can be provided. Models of diiTerentiation The examination of the salience of offence actions indicates that the consideration of any action in isolation from the others that may co-occur with it can be misleading. Any single action may be so common across offences or so ambiguous in its significance that its use as a basis for investigative inferences may suggest distinctions between offenders that are unimportant. Differentiation therefore needs to have foundations in an understanding of the processes that give rise to co-occurring patterns of criminal activity. Within the radex model the forms of saUence derive their specific meanings from the psychological themes which they Profiling and differentiation 2)1 reveal. A number of researchers have followed the implications of this by testing the hypothesis that these themes reflect the mode of interpersonal transaction that the offender uses to carry out the crime. One elaboration of this mode of interpersonal transaction is that put forward by Canter (1995a). He takes a more social psychological perspective on what Canter and Fritzon (1998) call the 'locus of desired effects'. The locus here is the role the offender assigns his victim during the crime. This model is a distillation of the findings reported by Canter and Heritage (1990). Rather than the five-fold model they proposed. Canter (1995a) argued that in more general terms the five models of transaction can be reduced to three general roles to which a victim may be assigned, i.e. where the offender: (1) treats the victim as an object (something just to be used and controlled through restraint and threat, often involving alternative gains in the form of other crimes such as theft); (2) sees the victim as a vehicle for the offender's own emotional state (e.g., anger and frustration (the victim is subjected to extreme violence and abuse)); and (3) sees the victim as a person (some level of pseudo-intimacy with attempts to create some sort of rapport or relationship). Canter (1995a) presents some evidence for this model as a basis for differentiating rapists. More recendy. Canter et al. (1998) have shown the model is supported with data from 97 paedophiles. Salfati and Canter (1999) used a somewhat different vocabulary in their study of 82 stranger homicides, but still presented an analogous threefold model. Hodge (in press) also found the model to be of value in her study of 88 US serial killers. Her particularly detailed argument and MDS results provide one of the clearest examples of this approach. She hypothesized that for those sexual serial murderers where the role of victim was as an object, the crime scene behaviours would reflect few emotional elements with litde interpersonal interaction. The offender would be unlikely to be influenced by the victims' responses, acting out a personal ritualized script, in which the victim plays no part as a human being. She also hypothesized that post-mortem injuries and sexual acts, as well as excessive violence and dismemberment would co-occur with these other indicators of the 'victim as object'. Hodge (in press) took the thematic focus on the role of victim is as a vehicle to reflect more overtiy emotional reactions. She points out that although the offender may well subject his victim to extreme violence similar to the offender who sees his victim as an object, there will be a difference in concern the offender has for the sort of people his victims represent to him in his personal life. Therefore, there is likely to be a substantial level of interpersonal interaction between victim and offender. Associated crime scene behaviours may include the use of restraints and there may be evidence that the victim was kept alive for a period of time. Where the role of the victim is as a person, Hodge (in press) hypothesized that the crime scene behaviour will reflect the importance of the victim as a particular person. She proposes this will be shown in the co-occurrence of variables that indicate the degree and style of interaction between the two. Excessive violence would be rare, and sexual activity would be more likely to be 'normal', such as full sexual intercourse prior to death and violence directed at specific areas of the body, especially the facial area. 38 David Canter 33 redress 7 j'eceptacle 10 asphix 22 autotheft 16 poses Victim as Object Victim as Person 6 distweap „.,/ , 19 bodypass specnat ol/neckup 25 loXjc 5unusual released ^ 34 implement j^multstah chemical 11 '^'setfire exmut 9 postmort proto 28 3 captive props 32 cutthroat38 36 kicked frenzy Victim as Vehicle blindfold 18 \35 hacked Figure 4. MDS analysis (smallest space analysis) of the actions of 88 US serial killers (from Hodge, in press). Numbers refer to the variable numbers in the original study. Brief titles for the variables are given on the plot; the full coding dictionary is given in the original study. As tbe earUer discussion of tbe radex model makes clear, tbis tbreefold classification is not meant to indicate distinct types of offender, but ratber themes that will be present in all offences to some degree. Tbe differences between offenders are in tbe empbases tbat any particular offender exhibits. Hodge (in press) tested tbese bypotbeses by carrying out an MDS analysis of 39 crime-related actions of tbe 88 kiUers she studied. The resulting two dimensional configuration is shown in Fig. 4. For fuU details of this analysis the original study should be consulted. As Hodge bypotbesized, regions of tbe MDS configuration can be distinguisbed that indicate the different emphases predicted by tbe tbreefold interpersonal model. To the right of the plot are those variables tbat suggest that the victim is dealt with as 'an object'. These activities have similarities to those associated with sadistic/lust murderers (Becker & Abel, 1978). NecrophiUac activity, cannibalism, backing tbe body, leaving it in a posed position and otber post-mortem activities are aU consistent with the victim being Uttle more tban something to use. There is no indication that the victim carries any emotional significance for the offender. To the bottom left of tbe plot are tbose actions tbat indicate that the victim acts as a vehicle for the offender. Tbe victim being beld captive and being involved in tbe script of tbe offender elaborate tbe underlying brutaUty of tbe offence. As Hodge points out, tbe significance of the victim to the offender can result in the Profiling and differentiation 39 direction of excessive violence to areas of the body that hold importance for the offender. Specific types of victim are selected, and sometimes restrained using designed crime kits (kit) and restraints (blindfolds). Hodge (in press) points out that to the top left of the plot are those behaviours that indicate that the offender perceives his victim as a person with whom his desire for some degree of interpersonal interaction is fulfilled. This theme may be indicative of tbe category of rape murder proposed by Groth, Burgess, and Holmstrom (1977). In such cases, the victim's responses are more likely to influence the offender's behaviour. In other words, the interaction is two way rather than only from offender to victim. Here, the victim is not only integral to the offender's script but has a 'speaking part'. The variables sex (full sexual intercourse) and dressing the victim after the sexual assault (redress) suggest some degree of emotional significance to the victim as a person. The taking of personal documents and belongings from the victim also shows an interest in the person rather than just her body. This study of serial killers illustrates how crime-related actions can be differentiated as a first step towards the development of models that will characterize the dominant themes in criminal bebaviour. It is of especial interest because it replicates findings from a number of different studies of criminal behaviour, lending support to the proposition that there may be similar underlying themes that differentiate many different crimes. Consistency between crimes and non-criminal actions The possibility of such consistencies has led some researchers to seek general models of criminal behaviour that will explain and predict these differences. Canter and Fritzon's (1998) use of action systems theory is one such approach. A more direcdy psychological approach has been proposed by Bennell, Alison, Stein, Alison, and Canter (1999). They developed the criminal consistency argument outlined by Canter (1995a), in which crime is seen as an extreme form of non-criminal activity, and is therefore likely to reflect variations that occur in ordinary day-to-day interpersonal activities. They examine the abuse of children and argue that the variations in the forms of abuse will parallel the variations in the more conventional interactions between adults and children. They therefore propose that the structure found in MDS analyses of child abuse will be a variant of the circumplex model reported by Schaefer (1997) in his study of variations in maternal behaviour. The results of their study show that the coercive basis of child abuse typically mirrors forms of control and the exploitation of trust that normally occur in conventional adult-child relationships. These studies are not alone in generating classification schemes for considering offenders. Some very valuable clinical studies have been carried out, for instance in relation to sex offenders (Grubin & Kennedy, 1991; Prentky, Cohen, & Seghorn, 1985). However, such studies often combine the characteristics of the offender with aspects of their actions in ways that reduce the possibilities for inferring one from the other. Future research must therefore build stronger bridges between these clinical studies and those carried out in the context of offender profiling. 40 David Canter Behavioural consistency If any offender commits a series of crimes there are questions about what is consistent across them that can be used in understanding the offender. This is very closely related to the problem of reUabiUty in aU forms of psychological measurement. It is also a central problem in many poUce investigations where attempts are being made to determine which of a number of offences have been committed by the same person. Canter (1995b) reports some success in comparing the patterns of behaviour across crimes using a simple measure of association, the Jaccard's coefficient Qaccard, 1908). In a more detaUed study, Grubin, KeUy, and Ayis (1997) examined 470 cases of sexual assault committed by 210 offenders. They used cluster analysis to show that offenders tended to have similar offending styles. They did this by dividing crimes into different components a priori: the form of control, the nature of the sexual activities, the mode of escape and the overall nature of the crime. Each of these was then examined to determine if offenders tended to be consistent in each of these aspects. The consistencies Grubin et al (1997) found are an important contribution to our understanding of criminal behaviour, but as the radex model iUustrates there is a risk that their results are contaminated by relationships between the different components of the offence. The radex model also raises the possibiUty that the consistencies found are a product of the frequencies of offence actions rather than co-occurrences across offenders. In order to overcome these difficulties Mokros (1999) used the positions of offenders' actions directly on an MDS analysis of rapists. Mokros (1999) used a smaller sample than Grubin et al. (1997)—126 sexual assaults committed by 42 offenders. He was nonetheless able to demonstrate that the actions of different crimes committed by the same offender were more Ukely to be close to each other on the MDS plot than the actions of different offenders. Taken together, the various studies of rapists' behaviours do show some Umited degree of consistency. However, there are few studies that have been carried out on other forms of crime. One notable exception is the study by Green, Booth, and Biderman (1976) that presciently used MDS techniques in combination with cluster analysis to demonstrate that the modus operandi of burglars did have a demonstrable statistical existence. Spatial consistency These studies do show, therefore, that whUst the individual actions of an offender may not aU be identical from one crime to the next, the themes that characterize those crimes may often be reasonably consistent. ConceptuaUy this may be regarded as the offenders operating within a Umited conceptual space, as can be defined by an area of an MDS configuration. But more directiy spatial consistencies have been found among serial criminals. Brantingham and Brantingham (1981) summarized the growing Uterature indicating the Umited area over which many offenders operated. Since that rime a number of researchers have demonstrated the practical utiUty of models of offender Profiling and differentiation 41 spatial consistency (Godwin & Canter, 1997; Kind, 1987; LeBeau, 1987; Rossmo, 1997). Canter and Gregory (1994) argued that the likely success of these models was a function of whether the offender was a 'commuter' or a 'marauder'. The latter tended to use some fixed base, often his or her home, as a focus for his or her activities. This means that gravitational models can be developed to derive the likely location of the home from knowledge of the location of their crimes. By contrast, those who 'commute' into an area to commit their crimes are less open to having their home's location modelled. There are interesting similarities between the role of daily activities in the spatial behaviour of 'marauding' offenders and the view that crime is a reflection of the non-criminal activities of offenders. This accords well with the routine activity theory of crime (Clarke & Felson, 1985), which is usually applied to instrumental crimes such as burglary. However, the spatial studies tend to have been of serial rapists and killers, indicating that at least in the choice of location these criminals often draw on their daily routines in some logical way. Inference The considerations above show that there is a growing understanding of the forms of differentiation that it is valid to make between criminals. These distinctions appear in some circumstances to reflect other aspects of a criminal's life besides the particular crime he or she has committed. This provides a reasonable basis for hypotheses about the association between actions in relation to a specific crime and other characteristics of an offender. Canter (1995b) characterized this inference of Characteristics from Actions as the 'profiling equation', suggesting that it potentially has all the complexity of canonical regression models. However, to date no researchers have tackled the full complexity of these equations, preferring to model focal aspects of them. As indicated, one recurring conceptual basis for these models can be seen as an elaboration of routine activity theory in which it is hypothesized that the offender will show some consistency between the nature of his or her crimes and other characteristics he or she exhibits in other situations. This is rather different from the many psychological models that attempt to explain criminality as being a product of psychological deficiencies (Farrington, 1998). The inference models used for profiling are less concerned with the prediction of criminality than with unravelling the structure it takes and how that structure connects with features of the offender that will be of interest during an investigation. These inference models draw upon the thematic approach that has been outlined above and in this regard show how far removed the approach is from the 'clues' of detective fiction. Any one criminal action may be unreliably recorded or may not happen because of situational factors. But a group of actions that together indicate some dominant aspect of the offender's style may be strongly related to some important characteristic of the offender. Davies, Wittebrod, and Jackson (1997) showed the power of this thematic approach. They demonstrated from their analysis of 210 rapes that if the offender took precautions not to leave 42 David Canter fingerprints, stole from the victim, forced entry and had imbibed alcohol, then there was a very high probabiUty, above 90%, tbat tbe offender bad prior convictions for burglary. Unfortunately Davies et al (1997) do not provide a detailed structural analysis of tbe relationsbips between all tbe activities tbat tbey considered. Tbey used a logistic regression tbat searcbes tbrougb tbe data to find the best matcbes, so that low level relationships that may add up to provide an overaU picture are ignored. However, the actions that tbey bring togetber to predict prior burglary indicate an offender wbo is determined to commit tbe crime and get away witb it, treating the victim as a resource or 'object' rather than a significant person. Salfati and Canter (1999) examined aU the actions togetber witb tbe cbaracteristics in tbeir study of 82 stranger bomicides. Tbeir analysis did reveal consistency in the themes across actions and characteristics. As with Davies et al.'s (1997) study, the clearest associations of criminal actions were witb previous offence bistory. Tbose murderers wbo stole non-identifiable property, wbo were careful not to leave forensic evidence and who hid or transported tbe victim's body were more Ukely to bave bad a custodial sentence, but interestingly were also more Ukely to bave served in tbe army. Tbe most developed exploration of thematic inference hypotheses is Canter and Fritzon's (1998) study of arsonists. They developed scales to measure four themes in the actions of arsonists derived from their action system model. They developed a further four scales to measure themes in the background characteristics of the 175 solved arson cases they studied. Tbeir table relating measures on aU four background scales to all four action scales sbowed tbat tbe strongest statisticaUy significant correlations were, as predicted, between actions and cbaracteristics that exhibited similar themes, and lowest between tbose tbat did not. These studies of inference are therefore slowly beginning to provide a basis for a more general tbeory of offender consistency. But tbey suffer from deaUng with the criminal as an individual independently of tbe social or organizational context in wbicb be or sbe operates. As Canter and AUson (1999) bave argued, tbe social processes tbat underUe groups, teams and networks of criminals can reveal much about tbe consistencies in criminal bebaviour and the themes that provide their foundation. A clear example of this is the study by Wilson and Donald (1999) looking at tbe different roles tbat are taken by teams of 'bit and run' burglars. Tbey demonstrated, for example, tbat tbe offender wbo was given tbe task of driving tbe getaway vebicle was most often likely to bave a previous conviction for a vebicle-related crime. In contrast, tbe criminal assigned tbe task of keeping members of tbe public at bay, or controlUng otbers wbo migbt interfere witb their crime (the 'heavy') was most likely to have a previous conviction for some form of violence offence. These results of consistency between social role and otber forms of criminal endeavour are tbus in keeping witb tbe general tbematic framework tbat is emerging tbrougb tbe studies of actual actions in a crime. Tbey lend support to a general model of criminal activity tbat recognizes tbe specific role tbat criminality plays in tbe Ufe of tbe offender. It furtber supports tbe perspective tbat, for tbe sorts of offenders considered in tbe studies cited, tbe style of criminaUty is an Profiling and differentiation 43 integral, natural part of the criminal's general lifestyle, not some special, atypical aspect of it. Implications Police forces throughout the world now regularly request descriptions from people with a psychological or criminological background of the likely characteristics of unknown offenders. They present the expert of their choice with details of the crime and then ask that individual to infer for them what those characteristics are likely to be. Until recendy there has been very litde research on which to base these inferences. As a consequence, the process these 'profilers' go through is often littie more than informed speculation. However, this does not appear to limit the desire of police officers to request such information. There is, therefore, an important area of study that examines what it is felt is achieved by this 'expert' input. A fruitful approach to understanding the reasons for the attractiveness of this input is provided by research that seeks parallels with the apparent attractiveness of astrology and psychic detection. The rhetorical devices used by psychic detectives have been shown by O'Keefe and vVlison (in press) to be influential in creating the impression of benefit through encouraging reinterpretation of ambiguities in self-referential ways by the target of these opinions. In much the same way as astrology charts are open to so many interpretations from which the gullible reader wül perceive the interpretation that makes most sense to him or her, so psychic detectives wül offer ambiguous comments that, whilst apparendy seeming to offer precise guidance, are actually ambiguous. Research suggests that many offender profiles achieve their attractiveness to police officers by similar means (Copson, 1995). Copson also notes that in only 3% of any of the cases did the profiler help identify the offender. Therefore, the current practice of seeking advice on a profile appears to be more of an insurance and reassurance policy than an investigative tool to aid direcdy in catching offenders. This practice of bringing in an 'expert' as a form of insurance policy has many risks associated with it. For example, police officers and psychologists may be engaged in an investigative folie a deuxf, where both parties are reinforcing each other's personal beliefs until they become increasingly convinced of a particular line of enquiry (Canter and Alison, 1999). The only way out of this is to follow Meehl's (1996) advice and develop beyond the 'clinical' to the 'actuarial'. The various empirically based models that are emerging suggest that the days of the 'heroic' expert are numbered. In some cases the principles that research supports can be presented so direcdy that they can be incorporated into police training. This is a consequence of the power of valid theories to summarize a great deal of information. The thematic consistency models, once elaborated, would not be beyond the understanding of most detectives. In other cases the research points to the possibilities of searching existing databases (Davies, 1997), or other forms of record of possible suspects, and then assigning priorities to the possible offenders (CofFey & Canter, in press). There are many practical difficulties in implementing such systems (Radedge & Jacoby, 1989). 44 David Ganter But there are many potential benefits if these difficulties can be overcome. Perhaps one of the most important potential benefits relates to civil liberties. Currently the personal opinion of 'experts' can lead to a person being dealt with as a prime suspect even though there is no overt basis for that judgment at all. At least with a computerized process, founded in explicit, empirically supported psychological models, the basis of the decisions can be overtly determined and tested for their reliability and validity. The slow accretion of scientific evidence, the development and test of theories and implementation of findings into computer-based, decision-support systems does not have the same dramatic power, or excitement, as the lone private investigator cracking the crime where the police have been unable to. But the systematic examination of the most appropriate ways to differentiate offenders has to be the proper basis for any professional derivation of inferences about offenders. It is also the basis for important new perspectives on the nature of crime and criminals. References Aked, J. P., Canter, D., Sanford, A. J., & Smith, N. 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Alison (Eds.), The social psychology of crime: Teams, groups, networks (Offender Profiling Series, Vol. Ill, pp. 127-152). Aldershot: Dartmouth. Received 8 October 1999 Copyright of Legal & Criminological Psychology is the property of British Psychological Society and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. J Police Crim Psych (2008) 23:51–60 DOI 10.1007/s11896-008-9028-5 Investigating the Reliability of the Violent Crime Linkage Analysis System (ViCLAS) Crime Report Melissa M. Martineau & Shevaun Corey Published online: 26 August 2008 # Springer Science + Business Media, LLC 2008 Abstract The Violent Crime Linkage Analysis System (ViCLAS) is a computerized investigative aid, developed by the Royal Canadian Mounted Police, which is used to increase information sharing and enable crime linkages in serious crime investigations. The current study examines the reliability of the ViCLAS Crime Report by calculating the level of agreement among two samples of police officers who received one of two fictitious crime scenarios; homicide (n = 116) or sexual assault (n = 121). Results from this study show that the observed inter-rater reliability among police officers completing the ViCLAS booklet was 79.30% for the homicide scenario, and 87.70% for the sexual assault scenario. Implications of the results are discussed. Keywords Crime linkage . ViCLAS . Reliability . Police data The Violent Crime Linkage Analysis System (ViCLAS) is a repository of behaviorally-focused crime data coupled with a complex query function. This computerized investigative aid assists trained police analysts in the identification of serial offenders and/or crime series by focusing on particular aspects of crime events (Collins et al. 1998; Wilson and Bruer 2008). ViCLAS was developed by the Royal Canadian Mounted Police (RCMP) in the early 1990s to increase information sharing relating to serious M. M. Martineau (*) Research and Development, Behavioral Sciences Branch, Royal Canadian Mounted Police, 1426 St. Joseph Blvd, Ottawa, ON, Canada K1A 0R2 e-mail: S. Corey Department of Psychology, Carleton University, 1125 Colonel By Dr, Ottawa, ON, Canada K1S 5B6 crime investigations, breaking the boundaries of police jurisdiction and enabling crime linkages nation wide (Collins et al. 1998). Crime linkage is defined as the process of identifying crimes that are behaviorally similar (i.e., exhibiting similarities in modus operandi), suggesting that they have been committed by a single offender (Woodhams et al. 2007; for more information on linkage analysis see Collins et al. 1998, Douglas and Munn 1992, and Hazelwood and Warren 2003). The RCMP, as well as the provinces of Ontario and Quebec, has created non-discretionary policies mandating the use of ViCLAS. Contributions by municipal police agencies in all other provinces are voluntary, and although submission rates vary by jurisdiction, many municipal agencies contribute case information. As a result, ViCLAS currently contains over 300,000 cases (Wilson and Bruer 2008). ViCLAS submissions are completed for the following case types, which are referred to as ViCLAS reportable crimes: solved, unsolved or attempted homicides; solved, unsolved or attempted sexual assaults; missing persons cases where foul play cannot be ruled out; unidentified human remains where foul play cannot be ruled out; nonparental or attempted abductions; solved, unsolved or attempted child luring and pornography (Collins et al. 1998; Wilson and Bruer 2008). Role of the Investigator When a police officer is investigating a ViCLAS reportable offence, they must complete a ViCLAS Crime Report (commonly referred to as the ViCLAS booklet) within 30 days of the commencement of their investigation. The investigator will complete the booklet either by hand or electronically. In order to complete the ViCLAS booklet, the 52 investigator will utilize all available information collected during the course of the investigation, which may include victim and witness statements, a crime scene analysis, and physical evidence. To assist in the completion of the Crime Report, investigators have access to a guide that provides a detailed description of each question contained in the booklet, definitions of included terms, and explanations of response options. Once completed, the Crime Report is forwarded to the provincial ViCLAS centre, where an analyst will conduct a quality review to assess the accuracy and completeness of the submission prior to data entry (Wilson and Bruer 2008). J Police Crim Psych (2008) 23:51–60 ViCLAS an attractive source of data for police research. Among Canadian criminal justice databases, ViCLAS provides more in-depth information relating to the behavioral aspects of violent crime than any other available data source. Other crime databases, such as the Canadian Police Information Centre (CPIC) or the many different police Report Management Systems (RMS), contain a wealth of information pertaining to criminal investigations. However, none of these systems have been designed to facilitate crime linkage analysis, and as such, none of them provide the amount of detailed, behaviorally based data that is available in ViCLAS; nor do they offer a query functionality as complex as that of ViCLAS. Investigative Utility of ViCLAS Following data entry, trained ViCLAS analysts examine and interpret case data, comparing information between the target case (i.e., the case currently being analyzed) and other cases within the database to identify potential linkages either by offender (i.e., attributing two or more crimes to a known/ identified offender) or by crime (i.e., identifying a crime series that has been perpetrated by the same unknown offender; Woodhams et al. 2007). When an analyst identifies a number of cases that share significant behavioral similarities (i.e., cases that exhibit a number of common verbal, physical or sexual behaviors), which suggests a common offender, the analyst will link the cases to form a potential series. The analyst then prepares a potential linkage report that is submitted to the police officer(s) assigned to the investigation, thereby providing the investigator(s) with a potential suspect, or suggesting the possibility that a single unknown offender is responsible for the crime series. Once a crime series has been identified, investigators within or across police jurisdictions may pool their resources and devise joint strategies to identify and capture the offender faster than would be possible if several police services ran simultaneous, unconnected investigations (Collins et al. 1998). By increasing the coordination of investigative efforts and opening lines of communication among investigators, ViCLAS aims to address the problem that Egger (1984) coined linkage blindness; the failure by police to link serial crimes to a common offender due to a lack of inter-departmental communication. Linkage reports, the product of crime linkage analysis, combine the knowledge gleaned through numerous investigations, highlighting case similarities and providing additional information that can be useful to police. Ideally, police officers will be able to confirm the linkage through further investigation in order to solve a previously unsolved case. While the main purpose of ViCLAS is to provide police with a mechanism for information sharing and an analytical tool for the linkage of serial crime, the type and volume of information contained within the system also makes The Importance of Consistent and Accurate Crime Reporting Some researchers posit that the quality of information contained in police reporting systems is questionable, and that a failure to accurately record case details can contribute to reductions in data reliability (Alison et al. 2001). Despite the fact that empirical research examining these issues is limited, such issues surrounding data quality are clearly important. For example, the quality of the data contained within ViCLAS will have an impact on crime analysis in terms of the caliber of resulting linkages. Indeed, inconsistent or inaccurate crime reporting can have a number of detrimental effects on violent crime linkage analysis. An analyst may fail to identify an existing linkage, erroneously deciding that a target case does not share enough commonalities with other recorded cases to be linked together. On the other hand, an analyst may link cases that in reality do not share a common offender. To the extent that consistent and accurate crime reporting is necessary for crime linkage analysis, it is also essential for other complementary investigative services, such as criminal profiling. Criminal profiling is commonly defined as “a technique for identifying the major personality and behavioral characteristics of an individual based upon an analysis of the crimes he or she has committed,” (Douglas et al. 1986, p. 405). As with linkage analysis, criminal profilers often rely on information gathered by investigators about a particular case or crime series to devise offender profiles. Inaccuracies in the reporting of crime event details may diminish the investigative utility of an offender profile. The quality of the data contained within investigative databases such as ViCLAS can also have an impact on the quality of empirical research conducted using this data. The integrity of such data is of particular concern for those conducting research in the area of linkage analysis and criminal profiling, as these studies typically rely on the information contained within such databases (e.g., ViCLAS, ViCAP, HITS, etc.). Thus, if this data were found J Police Crim Psych (2008) 23:51–60 to be unreliable or inaccurate, the findings from such studies would carry little weight. Several measures have been instituted to enhance the accuracy and completeness of the data entered into ViCLAS. These measures include the creation and distribution of a detailed Field Investigator’s Guide, which provides investigator’s with instructions on the completion of the ViCLAS Crime Report. In addition, as briefly discussed above, there is a quality control process in place whereby the Crime Report is reviewed by ViCLAS analysts in conjunction with all available case materials prior to data entry (Wilson and Bruer 2008). However, no empirical evidence exists to date indicating how consistently and accurately investigators complete the ViCLAS Crime Report. The Current Study The current study was conducted with the aim of filling the gap in empirically based knowledge relating to the reliability of police reporting when completing a ViCLAS Crime Report. This was accomplished by examining the Crime Reports of a sample of police officers who were exposed to one of two fictitious crime scenarios (one involving a sexual assault and the other a homicide). An examination of the consistency of their responses by crime type allowed us to determine the degree of reliability among officers. Method Sample Two-hundred and thirty seven non-commissioned police officers (i.e., police officers holding a rank of constable, corporal, sergeant or staff sergeant) participated in the study. The officers voluntarily completed the study as part of one of two courses offered at the Canadian Police College. Participants did not receive compensation or course credit for taking part in the study. Of the 237 police officers who participated in the study, 116 completed the ViCLAS Crime Report for the homicide scenario (the homicide group) while 121 completed the report for the sexual assault scenario (the sexual assault group). A description of both the homicide and sexual assault groups, in terms of length of service, experience with ViCLAS, and the specific crime types they were reporting on, can be found in Tables 1 and 2 respectively. 53 a consent form, c) a background questionnaire, d) a crime scenario, e) a copy of the Field Investigator’s Guide, and f) a blank ViCLAS Crime Report (ViCLAS booklet). Each package was assigned a number, which was used to match the background questionnaire with the completed ViCLAS Crime Report while protecting the participant’s anonymity. The background questionnaire was comprised of six questions relating to the participant’s experience: a) as a police officer, b) with ViCLAS, and c) as an investigator. The background questionnaire was used to describe the current study sample (see Tables 1 and 2). Fictitious crime scenarios Two crime scenarios, homicide and sexual assault, were created for use in this study. In order to create realistic crime scenarios, actual homicide and sexual assault case files were consulted and reviewed. To further ensure the realism of the scenarios, they were examined by a police officer and a ViCLAS analyst. Both crime scenarios were presented in the format of a police report, which is the document prepared by a police officer when they receive information pertaining to unlawful activity or a public complaint. This format was utilized because it is how police officers typically read cases. The police report in the current study included information regarding the crime (e.g., location of various scenes, specific violent and sexual behaviors exhibited by the offender, etc.), victim (e.g., name, address, physical descriptors, etc.), offender (e.g., name if known, physical descriptors, address, occupation, etc.), witnesses (e.g., name, relevance to the case, etc.), and evidence collected at the crime scene(s) (e.g., DNA samples, other physical evidence, etc.) in fixed field format (see Appendix A and B) as well as a narrative summary providing a chronological account of the event and how it occurred. Researchers interested in obtaining the narrative summaries should contact the first author. Materials Field investigator’s guide The Field Investigator’s Guide was provided to participants as a resource/reference to use when completing the ViCLAS booklet. This guide provides a more detailed description of each of the questions contained in the booklet, including an explanation of question inclusion or question meaning when appropriate, and definitions of response options that may be unfamiliar to some investigators. Investigators in the field have access to this guide when completing ViCLAS Crime Reports and thus the participants in the current study were also provided the opportunity. In other words, they were able to access the Field Investigator’s Guide at any point when completing the Crime Report. Study participants were provided with a package that contained in order the following: a) an information letter, b) ViCLAS crime report Each participant received a blank copy of the ViCLAS Crime Report in which they were 54 J Police Crim Psych (2008) 23:51–60 Table 1 Descriptive statistics and frequencies of the demographic variables for the homicide group (N=116) Variable n M(SD) Range Length of Service Total Number of ViCLAS Booklets Completed Number of Times Investigating the Case Involved in the Current Study 101 80 84 Previous ViCLAS Training Previously Completed a ViCLAS Booklet Experience with the Case Type in Current Study 100 102 102 14.81 (5.89) 30.07 (47.74) 9.08 (17.33) Yes 52 89 88 4–31 1–300 1–150 No 48 13 14 required to record the information contained within the case that they received (i.e., either the homicide or sexual assault scenario). The ViCLAS booklet is comprised of 156 questions divided into sections including: Administration (i.e., details relating to the investigating officer(s), classification of the offence, and when the crime occurred), Victim (i.e., details about personal information, traits, and behaviors of the victim), Offender (i.e., details about personal information, traits, and behaviors of the offender), Vehicle (i.e., details about the type of vehicle(s) involved in the offence), Scene (i.e., description of the place the crime occurred), Offence (i.e., details about the crime itself), Deceased Victim (i.e., details relating to the recovery of any deceased victims), Weapon (i.e., description of weapon(s) used in the commission of the crime), Biological Sample (i.e., details relating to any biological evidence found at the crime scene), and Summary (i.e., an overall narrative account of the crime under investigation). For a breakdown of the number of questions per section see Tables 3 and 4. The questions included in the Crime Report are designed to obtain information related to all aspects of the case (e.g., basic demographic information relating to involved parties, geographic locations, and an in-depth picture of the behavioral aspects of the offence) so that it can then be entered into the ViCLAS database for use in linkage analysis. The ViCLAS Crime Report employs both closed and open-ended question formats, which are either objective or subjective in nature. An example of a closed ended question is one asking the participant to identify the physical build of the victim from a set of response options ranging from small (thin) to obese. An example of an open-ended question is one asking the participant to identify any outstanding physical features of the offender in the absence of specific response options. Objective questions deal with subject matter that is concrete, such as the sex of the victim or offender. Subjective questions require participants to formulate an opinion based on the available case information, such as identifying the motive for the crime. While the ViCLAS booklet contains a total of 156 questions, the current analysis is based on a subset of these questions, differing by crime scenario (145 questions for the homicide scenario and 118 for the sexual assault scenario). Those questions that were not included in either scenario (i.e., 11 questions) were eliminated from the analysis due to the fact that they were administrative in nature and/or they were not of interest in the current study. For example, one of the administrative questions asks participants to indicate the investigator’s name. Since the study was completed anonymously, this was not appropriate. Another example of such a question is one that asks participants to provide a narrative summary of the offence. Due to the length and detail of this question, content analysis would be required and was beyond the scope of the current study. Twenty-seven additional questions were eliminated from the analysis of the sexual assault scenario because they were not pertinent to the specific case. For example, information relating to involved vehicles and deceased victim were not included in the sexual assault scenario, as no vehicle was utilized in the commission of Table 2 Descriptive statistics and frequencies of the demographic variables for the sexual assault group (N=121) Variable n M(SD) Range Length of Service Total Number of ViCLAS Booklets Completed Number of Times Investigating the Case Involved in the Current Study 111 112 100 Previous ViCLAS Training Previously Completed a ViCLAS Booklet Experience with...
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Example of a base rate fallacy.
A base rate fallacy recently occurred when profilers failed to consider a particular crime's
possibilities. Instead, they focused on the obvious data and evidence collected at the crime scene.
Due to this, they did not explore all possible angles of the crime and ended up heavily suspecting
the wrong person for the crime committed (Wixted et al., 2019). If they had continued searching
and asking the right questions, they would have got the right suspect for the crime. Stereotyping
is also a common base rate fallacy where certain types of people or gender are considered more
likely to comment on certain crimes than others.
The best approach for offender profiling.
The statistica...

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