Current Forensic Practice Research Articles

The Daubert/Kumho Implications of Observer Effects in Forensic Science: Hidden Problems of Expectation and Suggestion

After the Supreme Court's decision in Kumho Tire v. Carmichael and the recent amendment of Federal Rule of Evidence 702, proffers of expert testimony will have to be found reliable for the particular application of the asserted expertise to the task at hand. That is, expertise which is reliable in some global sense, which might apply to other cases but not to the particular application before the court, does not satisfy the requirements for admission. With that in mind, this article examines the phenomoenon of and the vulnerability of forensic science examinations to such observer effects. Observer effects occur when the results of an examination are distorted by the context and state of the observer, including the observer's expectations and desires. The article reviews the findings and practices of a range of scientific fields concerning such observer effects and their control, with special attention to the relevant research and theory from cognative and social psychology. This literature establishes that in virtually every area of human judgment, such observer effects have a relentless and sometimes dramatic effect on the accuracy of results. The article then examines current forensic science practice in light of that research, concluding that forensic science practice is far behind most scientific fields in controlling for such effects, leaving the reliability and accuracy of many forensic science results in doubt. The article then suggests practical ways in which forensic science practice can be changed to reduce such problems, such as the adoption of blind testing regimes. Finally, the article analyzes the current state of the law under Kumho Tire and Rule 702, concluding that the results of forensic science examinations are in danger of being excluded if their reliability continues to be undermined by the failure to control observer effects.

The Daubert/Kumho Implications of Observer Effects in Forensic Science: Hidden Problems of Expectation and Suggestion

After the Supreme Court's decision in Kumho Tire v. Carmichael and the recent amendment of Federal Rule of Evidence 702, proffers of expert testimony will have to be found reliable for the particular application of the asserted expertise to the task at hand. That is, expertise which is reliable in some global sense, which might apply to other cases but not to the particular application before the court, does not satisfy the requirements for admission. With that in mind, this article examines the phenomoenon of and the vulnerability of forensic science examinations to such observer effects. Observer effects occur when the results of an examination are distorted by the context and state of the observer, including the observer's expectations and desires. The article reviews the findings and practices of a range of scientific fields concerning such observer effects and their control, with special attention to the relevant research and theory from cognative and social psychology. This literature establishes that in virtually every area of human judgment, such observer effects have a relentless and sometimes dramatic effect on the accuracy of results. The article then examines current forensic science practice in light of that research, concluding that forensic science practice is far behind most scientific fields in controlling for such effects, leaving the reliability and accuracy of many forensic science results in doubt. The article then suggests practical ways in which forensic science practice can be changed to reduce such problems, such as the adoption of blind testing regimes. Finally, the article analyzes the current state of the law under Kumho Tire and Rule 702, concluding that the results of forensic science examinations are in danger of being excluded if their reliability continues to be undermined by the failure to control observer effects.

Can routinely combined analysis of glucose and lactate in vitreous humour be useful in current forensic practice?

To confirm and extend previous research concerning glucose and lactate in vitreous humour, we investigated a randomly selected study population of 271 forensic cases. On the whole, we find our results agree with those of previous studies, but we add certain observations. First, when we considered the sum value of glucose and lactate in the vitreous humour, we found that not only diabetes patients are included in the higher range group (values > or = 430 mg%): intensive reanimation or prolonged or intense agony should also be taken into account. Indeed, when we split our study group into acute agony and prolonged agony subgroups, we noticed a statistically significant difference; persons dying after protracted agony showed a higher sum value, which can be explained in terms of biophysical dynamics. Second, a positive correlation was found between the lactate and the sum values on one hand, and the postmortem interval on the other. However, the vitreous glucose, lactate, and sum values are so dispersed that a precise determination of the postmortem interval cannot be obtained on the basis of these parameters. Additionally, we compared several causes of death, but unfortunately, we did not manage to reveal that some causes of death were specifically limited to high or low concentrations. Indeed, the statistically significant differences in sum values could easily be explained by factors such as intensity of agony, reanimation attempts, or iatrogenic interventions (e.g., glucose infusions). Nonetheless, when the death scene as a whole is unclear or confusing, analysis of the vitreous humour can provide some insights, provided that the other autopsy findings are also taken into consideration.

Can routinely combined analysis of glucose and lactate in vitreous humour be useful in current forensic practice?

To confirm and extend previous research concerning glucose and lactate in vitreous humour, we investigated a randomly selected study population of 271 forensic cases. On the whole, we find our results agree with those of previous studies, but we add certain observations. First, when we considered the sum value of glucose and lactate in the vitreous humour, we found that not only diabetes patients are included in the higher range group (values > or = 430 mg%): intensive reanimation or prolonged or intense agony should also be taken into account. Indeed, when we split our study group into acute agony and prolonged agony subgroups, we noticed a statistically significant difference; persons dying after protracted agony showed a higher sum value, which can be explained in terms of biophysical dynamics. Second, a positive correlation was found between the lactate and the sum values on one hand, and the postmortem interval on the other. However, the vitreous glucose, lactate, and sum values are so dispersed that a precise determination of the postmortem interval cannot be obtained on the basis of these parameters. Additionally, we compared several causes of death, but unfortunately, we did not manage to reveal that some causes of death were specifically limited to high or low concentrations. Indeed, the statistically significant differences in sum values could easily be explained by factors such as intensity of agony, reanimation attempts, or iatrogenic interventions (e.g., glucose infusions). Nonetheless, when the death scene as a whole is unclear or confusing, analysis of the vitreous humour can provide some insights, provided that the other autopsy findings are also taken into consideration.

Assessment of malingering with simulation designs: threats to external validity.

Comprehensive forensic evaluations are predicated on the accurate appraisal of response styles that may affect evaluatees' clinical presentation and experts' conclusions associated with psycholegal issues. In the assessment of malingering, forensic experts often rely heavily on standardized measures that have been validated exclusively via analogue research. While such research augments internal validity, the threats to external validity are readily apparent. As the first study of these threats, type of incentive (positive versus negative), context (a familiar versus unfamiliar scenario), and relevance to the participants was investigated systematically with a between-subjects factorial design. A sample of 231 undergraduates was asked to either (a) feign major depression and given an easily understood description of this disorder or (b) serve as controls responding honestly. They were administered a brief measure of psychopathology (Hopkins Symptom Checklist; Derogatis, Lipman, Rickels, Uhlenhuth, & Covi, 1974) and a recent screen for malingering (Screening Inventory of Malingered Symptoms or SIMS; Smith, 1992) in 1 of 18 experimental conditions. Results suggested that incentive had a main effect on the SIMS. More specifically, simulators under negative incentives appeared more focused in their feigning; they produced more bogus depressed symptoms, but fewer symptoms unrelated to depression. Interactions were also observed between context and incentive, and context and relevance. Implications of these results are explored for both analogue research on malingering and current forensic practice.

A method for quantifying differentiation between populations at multi-allelic loci and its implications for investigating identity and paternity.

A method is proposed for allowing for the effects of population differentiation, and other factors, in forensic inference based on DNA profiles. Much current forensic practice ignores, for example, the effects of coancestry and inappropriate databases and is consequently systematically biased against defendants. Problems with the 'product rule' for forensic identification have been highlighted by several authors, but important aspects of the problems are not widely appreciated. This arises in part because the match probability has often been confused with the relative frequency of the profile. Further, the analogous problems in paternity cases have received little attention. The proposed method is derived under general assumptions about the underlying population genetic processes. Probabilities relevant to forensic inference are expressed in terms of a single parameter whose values can be chosen to reflect the specific circumstances. The method is currently used in some UK courts and has important advantages over the 'Ceiling Principle' method, which has been criticized on a number of grounds.

The Case for Using Nontraditional Judges in Forensic Contests

The forensics community should reintroduce the use of nontraditional judges in forensics tournaments. Diversifying the judging pool, while challenging tournament directors, will improve the educational value of forensics. The addition of nontraditional judges also will strengthen public support of the activity, and help forensics increase cultural diversity. This essay will build the case for using more nontraditional judges in forensic contests. I will discuss three benefits of increased use of nontraditional judges and consider some workability issues connected with their use. TRADITIONAL VERSUS NONTRADITIONAL JUDGES: HOW BEST TO EDUCATE STUDENTS? We may define a nontraditional forensic judge as a person with either limited training in contest judging or limited current experience in judging. Authors sometimes describe judges with limited experience as lay judges. Lay judges typically did not participate in forensics while students. People with limited current experience may include competitively inactive former competitors or forensics teachers. The common characteristic of both groups is their relative unfamiliarity with the nuances of current forensic practices. They may understand the structures of forensics contests but are not familiar with how situational norms affect actual practice. The issue of judging qualifications in forensic contests is neither recent nor trivial. Cox and Honse (1991) describe the long running discussion, particularly in the debate community, regarding the necessity of using trained listeners to judge debates. This discussion has centered on two questions: determining the goals of contest speaking; and identifying the necessary qualifications of a judge to achieve those goals. Most observers agree that contests include both educational and competitive aims. Students engage in contest speaking to improve their skills in areas like research, analysis and communication. Simultaneously, they are also competing against each other in pursuit of competitively driven outcomes, such as awards and other recognition. The role of competition is to provide an experiential learning framework for students to test and improve their learning skills. Competitive and educational goals in forensics often conflict. Competition sometimes causes people to short-cut appropriate educational behavior while pursuing competitive goals. This tension between competitive and educational goals underscores the important roles played by contest judges. Bartanen (in press) identifies three functions of the contest judge: educator, referee, and trustee of the activity. As an educator, the judge must help students learn research, analysis and communication skills by providing competent and appropriate comments about the content of their speeches or arguments. The educational function requires the judge to understand and apply the fundamentals of debate or individual events and to co-gently identify areas needing improvement. As a referee, the judge must appropriately apply contest rules and render a fair and impartial decision. This referee function requires the judge to understand both the structural (contest rules) and situational (nuances of competitive speaking and debating) elements of competition. As a trustee, the judge is responsible for maintaining the ethical and aesthetic standards of the activity. The judge must represent the larger community and apply aesthetic, ethical and rational standards that reinforce the utility of forensics as rational discourse. The judge, in other words, insures that debaters and speakers employ (in Wallace's use of the term) good reasons. Educators disagree about the necessary qualifications of people to fulfill these roles. Many educators believe that people trained in competitive forensics are the best contest judges. Robert Gass (1988), for example, advocates the use of trained judges who can promote high educational standards. Other critics (cited by Cox and Honse) oppose nontraditional judges because they believe, usually based on anecdotal evidence, that those judges evaluate contest winners randomly or only on contestants' delivery skills. …

Review of Hypnosis: Current Clinical, Experimental and Forensic Practices.

Review of Hypnosis: Current Clinical, Experimental and Forensic Practices.