The effect of contextual information on decision-making in forensic toxicology

Contextual bias in forensic toxicology decisions: A follow-up empirical study from China

The impact of contextual bias has been demonstrated repeatedly across forensic domains; however, research on this topic in forensic toxicology is very limited. In our previous study, experimental data from only one context version were compared with the actual forensic biasing casework. As a follow-up, this controlled experiment with 159 forensic toxicology practitioners was conducted, to test whether knowledge of different contextual information influenced their forensic decision-making. Participants in different context groups were tasked to identify testing strategies for carbon monoxide and opiate drugs. The results of chi-squared tests for their selections and two context groups exhibited statistically significant differences (p < 0.05 or p < 0.01). These findings show contextual information can bias forensic toxicology decisions about testing strategies, despite it is a relatively objective domain in forensic science.

A model of evaluative opinion to encourage greater transparency and justification of interpretation in postmortem forensic toxicology

Over the past decades, the calls to improve the robustness of interpretation in forensic science have increased in magnitude. Forensic toxicology has seen limited progress in this regard. In this work, we propose a transparent interpretive pathway for use in postmortem forensic toxicology cases. This process allows the selection of the interpretive methodology based on the amount of previous information that is available for the drug(s) in question. One approach is an assessment of various pharmacological and circumstantial considerations resulting in a toxicological significance score (TSS), which is particularly useful in situations where limited information about a drug is available. When there is a robust amount of case data available, then a probabilistic approach, through the evaluation of likelihood ratios by the forensic toxicologist and of prior probabilities by the fact finder, is utilized. This methodology provides a transparent means of making an interpretive decision on the role of a drug in the cause of death. This will allow the field of forensic toxicology to take a step forward in using best practice in evaluative reporting, a tool already used by many other forensic science disciplines.

Operation makalu air crash: influence of cognitive and human factors on decision-making

Two onboard crew members lost their lives in the fatal Makalu Air Cessna Grand Caravan 208B domestic cargo flight crash on May 16, 2018. The Disaster Victim Identification (DVI) procedure comprises external examination, photography, DNA collection, fingerprint collection, postmortem examination, antemortem information collection from the family members, and reconciliation. The major challenge of this operation was dealing with cognitive bias. The antemortem dental information of one of the deceased was revealed to the forensic experts just before the postmortem examination. This influenced the testing strategies. There was a tendency to neglect the complete dental examination presuming the identification was established. Later, during a thorough examination, the forensic odontologist realised that the initial decision was erroneous. Furthermore, there are few experience-based resources available to resolve cognitive bias issues. The authors begin by summarising complicated operations in which they have been involved, followed by a discussion of the key sources of cognitive bias along with the solution to resolve these issues in DVI preparedness planning.

Objectivity is a myth that harms the practice and diversity of forensic science

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Forensic science data are theory laden; pure scientific objectivity is a myth.

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Upholding this myth marginalizes forensic scientists with subjective positionalities

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Objectivity rhetoric is exclusive; ethical forensic science needs diverse perspectives.

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Espousing objectivity prevents us from supporting the communities we serve.

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Mitigated objectivity acknowledges implicit bias, constraining it via quality control.

The biasing impact of irrelevant contextual information on forensic odontology radiograph matching decisions

The potential biasing effect of irrelevant context information on the forensic odontology method of radiograph-based identification has never been empirically investigated despite being a recognized problem in other forensic science disciplines. This study examines the effect of irrelevant context information on the probability judgment of match (JOM) of practicing forensic odontologist and dentist participants who were asked to match pairs of dental radiographs supplemented with irrelevant case information. The irrelevant case information contained domain task-irrelevant context information which varied in strength (strong or weak). It suggested either supportive or contradictory bias relative to the actual match status of the radiograph pairs. The dental radiographs consisted of verified match and non-match radiographs pairs sampled and de-identified from actual forensic cases. Changes in accuracy and JOM between supportive and contradictory contexts conditions revealed a contextual bias. Mixed model analysis showed that strong supportive context increased the odds ratio of correct decisions by a factor of 2.4 [1.23, 4.46]; p = 0.0097. Consistent with the biasing effect, the JOM score differences between strong supportive and contradictory irrelevant context information were 1.03 and 0.43 respectively for the non-match and match decisions. The direction of context suggestion (p = 0.0067), the radiograph match status (p = 0.014), and their interactions (p = 0.0061), were all found to impact the participants' decision. The weak context information was not strong enough to have a significant effect on accuracy or JOM scores. This study demonstrates that radiograph match judgment is affected and can be biased by strong irrelevant contextual information.

The impact of contextual information on decision-making in footwear examination: An eye-tracking study

In order to investigate whether context factors and expectations might potentially influence the decision-making of forensic footwear examiners, we collected the gaze process of experts examining the shoeprint image sets through the eye-tracking recorder. Additional to eye movement data as an objective measure, questionnaires were completed, and survey was conducted afterwards. Twenty-three qualified examiners assessed the similarity among shoe images for 22 different cases, including three sets were laterally reversed. We divided the experiment into two sessions, and then compared the examiners' performance with and without contextual information. The results showed the effects of contextual bias manipulate on both behavioral data and eye tracking data. The consensus and accuracy of examiners with contextual information were higher than those without contextual information. In the eye-tracking data, there is a significant difference between fixation counts and saccadic counts under contextual information. In addition, we found that the contextual information produced significant changes in inter-examiner consistency as measured by the Earth Mover Distance metric. However, there is no significant statistic differences in saccadic amplitude and total fixation duration of the examiners after exposure to contextual information. Our research results are instructive for understanding the cognitive process of shoeprint examination involved in real cases. In this process, stimuli related to context factors may affect decision-making and behavior. Implications for contextual effect causes are discussed.

Biasability and reliability of expert forensic document examiners

The performance of experts can be characterized in terms of biasability and reliability of their judgments. The current research is the first to explore the judgments of practicing forensic document experts, professionals who examine and compare disputed handwritten evidence to handwriting exemplars of individuals involved in criminal or civil litigation. Forensic handwriting experts determine if questioned and known handwritten items are of common authorship or written by different individuals, and present their findings in legal proceedings. The expert participants in our study (N=25) were not aware that they were part of a research study. Thirteen participants were led to believe that they were working on a case commissioned from the prosecution and the other twelve that it was for the defense. We did not find evidence in this study that this information biased their judgments, which may make sense since document examiners (in contrast to many other forensic domains) do not primarily work within an organizational forensic laboratory culture. The lack of bias in our findings may have been also due to the stimuli we used or/and the great variability in the judgments within each group, reflecting a lack of consistency in conclusions among examiners. A detailed discussion of our findings is presented along with the limitations that may have affected our results.