Brent Snook

Unobtrusive measurement: using police information for forensic research:

This article explores how unobtrusive research methods popularized by Webb et al. (1966) can be utilized in forensic research. In particular, the value of the approach is considered with special reference to examining investigative processes and criminal behaviour. Webb et al.’s three non-reactive types of unobtrusive measures (physical traces, archival material and simple observation) are discussed in relation to a variety of types of material collected across the course of police enquiries. The breadth and variation of this material is emphasized with special consideration of its utility for research. We illustrate how the limitations and benefits identified by Webb et al. are echoed within the forensic domain and how close attention to the methods of collecting such material developed by researchers may improve the effectiveness of investigations.

The criminal profiling illusion: what's behind the smoke and mirrors?

There is a belief that criminal profilers can predict a criminals characteristics from crime scene evidence. In this article, the authors argue that this belief may be an illusion and explain how people may have been misled into believing that criminal profiling (CP) works despite no sound theoretical grounding and no strong empirical support for this possibility. Potentially responsible for this illusory belief is the information that people acquire about CP, which is heavily influenced by anecdotes, repetition of the message that profiling works, the expert profiler label, and a disproportionate emphasis on correct predictions. Also potentially responsible are aspects of information processing such as reasoning errors, creating meaning out of ambiguous information, imitating good ideas, and inferring fact from fiction. The authors conclude that CP should not be used as an investigative tool because it lacks scientific support.

PEERING INSIDE A CANADIAN INTERROGATION ROOM An Examination of the Reid Model of Interrogation, Influence Tactics, and Coercive Strategies

This study sought to shed light on the interrogation process through analysis of 44 video-recorded police interrogations of suspects in criminal cases. Results showed that, on average, interrogators used 34% of the components composing the nine-step Reid model of interrogation. Approximately 27% of the interrogations met Leos criteria for a coercive interrogation; minimization tactics were observed slightly more than maximization tactics; and most interrogations followed the guidelines, suggestions, and themes endorsed by Inbau, Reid, Buckley, and Jayne. In addition, confessions were positively associated with the proportion of core Reid components, the number of influence tactics, and the number of coercive strategies observed. Confessions were not associated with the number of discouraged denials but were positively associated with the number of alternative questions provided. The implications of these findings for interrogation practices and research are discussed.

Simply criminal: predicting burglars' occupancy decisions with a simple heuristic.

Rational choice theories of criminal decision making assume that offenders weight and integrate multiple cues when making decisions (i.e., are compensatory). We tested this assumption by comparing how well a compensatory strategy called Franklin’s Rule captured burglars’ decision policies regarding residence occupancy compared to a non-compensatory strategy (i.e., Matching Heuristic). Forty burglars each decided on the occupancy of 20 randomly selected photographs of residences (for which actual occupancy was known when the photo was taken). Participants also provided open-ended reports on the cues that influenced their decisions in each case, and then rated the importance of eight cues (e.g., deadbolt visible) over all decisions. Burglars predicted occupancy beyond chance levels. The Matching Heuristic was a significantly better predictor of burglars’ decisions than Franklin’s Rule, and cue use in the Matching Heuristic better corresponded to the cue ecological validities in the environment than cue use in Franklin’s Rule. The most important cue in burglars’ models was also the most ecologically valid or predictive of actual occupancy (i.e., vehicle present). The majority of burglars correctly identified the most important cue in their models, and the open-ended technique showed greater correspondence between self-reported and captured cue use than the rating over decision technique. Our findings support a limited rationality perspective to understanding criminal decision making, and have implications for crime prevention.

Let ’em Talk! A Field Study of Police Questioning Practices of Suspects and Accused Persons

The real-life questioning practices of Canadian police officers were examined. Specifically, 80 transcripts of police interviews with suspects and accused persons were coded for the type of questions asked, the length of interviewee response to each question, the proportion of words spoken by interviewer(s) and interviewee, and whether or not a free narrative was requested. Results showed that, on average, less than 1% of the questions asked in an interview were open-ended, and that closed yes–no and probing questions composed approximately 40% and 30% of the questions asked, respectively. The longest interviewee responses were obtained from open-ended questions, followed by multiple and probing question types. A free narrative was requested in approximately 14% of the interviews. The 80–20 talking rule was violated in every interview. The implications of these findings for reforming investigative interviewing of suspects and accused persons are discussed.

It’s no Riddle, Choose the Middle The Effect of Number of Crimes and Topographical Detail on Police Officer Predictions of Serial Burglars’ Home Locations

This study examines the effect of the number of crimes and topographical detail on police officer predictions of serial burglars’ home locations. Officers are given 36 maps depicting three, five, or seven crime sites and topographical or no topographical details. They are asked to predict, by marking an X on the map, where they thought each burglar lived. After making their predictions on half of the maps, officers randomly receive either no training or training in one of two simple decision-making strategies. The accuracy of predictions at baseline and retest is measured as the distance between the predicted and actual home locations, and these accuracy scores are compared to a commonly used geographic profiling system. Results show that training significantly improved predictive accuracy, regardless of the number of crime locations or topographical detail presented. In addition, trained participants are as accurate as the geographic profiling system.

Validities and Abilities in Criminal Profiling: A Critique of the Studies Conducted by Richard Kocsis and His Colleagues

In a recent issue of this journal, Kocsis reviewed the criminal profiling research that he and his colleagues have conducted during the past 4 years. Their research examines the correlates of profile accuracy with respect to the skills of the individual constructing the profile, and it has led Kocsis to draw conclusions that are important to the profiling field. In this article, the authors review the contributions of the Kocsis studies and critique their methodological and conceptual foundations. The authors raise a number of concerns and argue that data from the Kocsis studies fail to support many of the conclusions presented in his recent review. The authors present evidence in support of their assertions and provide recommendations that will allow future research in the area to generate data that are more meaningful and generalizable.

Problems of classification in investigative psychology

Problems of classification in the field of Investigative Psychology are defined and examples of each problem class are introduced. The problems addressed are behavioural differentiation, discrimination among alternatives, and prioritisation of investigative options. Contemporary solutions to these problems are presented that use smallest space analysis, receiver operating characteristic analysis, and probability functions.

Searching for a Needle in a Needle Stack: Combining Criminal Careers and Journey‐to‐Crime Research for Criminal Suspect Prioritization

This paper considers a suspect prioritization technique and tests its validity using a sample of commercial armed robbery offences from St John’s, Newfoundland, Canada. The proposed technique is empirically grounded in criminal careers and journey‐to‐crime research. Suspects with a previous criminal history are selected and ranked in ascending order by the distance they live from the location of the crime in question, with the nearest suspect given highest priority. Effectiveness is measured by the percentage of ranked suspects that needs to be searched before the offender is identified. Results show that 65% of the robbers were identified in the top 10% of ranked suspects. Limitations and proposed refinements are discussed in terms of future prioritization strategies and policing research.

The Violent Crime Linkage Analysis System A Test of Interrater Reliability

The interrater reliability of an internationally renowned crime linkage system—the Violent Crime Linkage Analysis System (ViCLAS)—was tested. Police officers (N = 10) were presented with a case file and asked to complete a ViCLAS booklet. The level of occurrence agreement between each officer was calculated. Results showed a 30.77% level of agreement across the 106 variables examined. Agreement ranged from 2.36% for weapon variables to 62.87% for administration variables. Only 11 (10.38%) of the variables reached an acceptable level of agreement. Concerns pertaining to the validity of inferences produced using ViCLAS data are discussed, along with potential explanations for the findings, limitations of the study, and future research directions.