Public beliefs about the accuracy and importance of forensic evidence in the United States

Public/family concerns for providing DNA in missing persons cases: Paper 2: The main concerns raised and implications for policing policy

Identification of unidentified human remains, and long-term missing persons (LTMP) is imperative, allowing for missing persons to be reunited with their families, which could provide closure to families experiencing ongoing ambiguity surrounding the situation. However, identification remains problematic for several reasons, including the absence of DNA provision in the investigation. The research reported here is the second in a two-part series exploring public/family support for providing DNA in LTMP cases. In the first study, quantitative results showed that participants had concerns when asked if they thought there would be implications for a person providing DNA to police in LTMP cases. The aim of this second study was to explore further using qualitative methods the nuances and themes underpinning concerns for providing DNA in LTMP cases. Participants described their concerns about providing DNA in four hypothetical LTMP case scenarios (a child, an adult with dementia, a runaway 19-year-old adolescent, and an estranged adult). Through thematic content analysis, ten themes were identified. Nine themes run across all four LTMP case scenarios. The tenth theme was only observed in two scenarios; cases involving adolescents with a history of runaway, and in cases involving adults estranged from their family. Results showed public concerns differed according to LTMP case circumstances. Key findings point to public education about how DNA is used in LTMP investigations, the applicable legislation relating to police use of DNA in investigations and increasing public awareness around the benefits of DNA use in LTMP investigations. Potentional policy options are discussed that could guide the future development of nuanced police practice in different types of LTMP cases.

Forensic odontology: Wrong convictions, "bad apples" and "the innocence files"

Forensic odontology (FO) provides expert testimony; however, new criticism has identified FO as one of the fields that must strengthen its scientific foundations. The recent Netflix documentary titled "The Innocence Files", featuring wrongful convictions, dedicates three of its nine episodes almost exclusively to bite mark identification (BMI), one of the most questioned tests performed by FO. Although most of the FO fields have an undoubted utility in forensic and juridical context, only BMI has been questioned in recent years; the derogatory expression "Junk science" is used continuously in the documentary almost as a synonym for FO. We present a scoping review of cases reported in the US National Registry of Exonerations in which FO was false or misleading forensic evidence (F/MFE) leading to wrongful convictions. Although in the 26 cases identified the only declared F/MFE was the BMI (excluding any other type of dental expertise), only in 2 cases (7.69%) was F/MFE the sole contributing factor, and in 4 cases (15.38%) there was F/MFE plus three additional factors. Official misconduct was detected in 19 cases (73.08%) and perjury or false accusation in 16 cases (61.54%). It has already been mentioned how dangerous it is to consider FO as synonymous with "bite mark identification", or even to publicly provide incorrect or decontextualized information. This review shows that erroneous convictions have been exclusively in the field of BMI, and that FO encompasses much more than just BMI. The relationship between the media and forensic sciences has been strained. The perspective of the new culture of risk management in forensics is also discussed.

Diversity in forensic sciences: Black, Indigenous, and People of Color (BIPOC) representation in different medicolegal fields in the United States

The benefits of a diverse and inclusive working environment are well documented. This study examined forensic science literature, demographic data reported from professional organizations, and demographic surveys to compile information regarding racial and ethnic diversity within different subdisciplines of forensic science. Results showed that practitioners self-identified as Black or Hispanic were underrepresented in scientific fields closely related to forensic science. Moreover, Black, Indigenous, and People of Color (BIPOC) students were underrepresented at the undergraduate level, despite increasing college enrollments. This lack of representation may have consequences on knowledge production and innovation. By recognizing the current status of diversity in forensic science, this study is the first step toward mitigating the trend of underrepresentation. We encourage professional organizations to be transparent about the diversity in their membership and provide actual practitioner demographic statistics. These data are beneficial to studying the effects of underrepresentation and developing effective strategies to improve representation.

Ambient lighting, use of outdoor spaces and perceptions of public safety: evidence from a survey experiment

Observational evidence suggests that better ambient lighting leads people to feel safer when spending time outdoors in their community. We subject this finding to greater scrutiny and elaborate on the extent to which improvements in street lighting affect routine activities during nighttime hours. We report evidence from a survey experiment that examines individuals’ perceptions of safety under two different intensities of nighttime ambient lighting. Brighter street lighting leads individuals to feel safer and over half of survey respondents are willing to pay an additional $400 per year in taxes in order to finance a hypothetical program which would replace dim yellow street lights with brighter LED lights. However, poor lighting does not change people’s willingness to spend time outdoors or to engage in behaviors which mitigate risk. Results suggest that street lighting is a means through which policymakers can both control crime and improve community well-being.

Development of an instrument for assessing the quality of forensic evidence and expert testimony from three feature-comparison methods: DNA, voice, and fingerprint analysis

In a context of rising violence and long-lasting impunity, in 2008, Mexico's criminal justice system underwent a radical change from an inquisitorial model to an adversarial one, to make it more effective, transparent, and expeditious. The new system tasked judges with publicly determining the admissibility of forensic evidence, as well as assessing its technical quality and probative value-tasks for which they currently receive little to no training. With the aim of contributing to the consolidation of the adversarial model, a comparative framework-in the form of a checklist-of the analysis of fingerprints, DNA samples, and voice recordings was created. To do so, a review of the academic literature, published reports, and guidelines was performed. The collected data were synthesized and submitted to a panel of Mexican judges, who provided feedback on its adequacy. The framework focuses on the steps on which quality assurance of forensic evidence depends, organized in five discrete stages that span from the collection of samples at the scene of a crime to the presentation of evidence at trial, specifying the main technical criteria experts should state to allow a decision maker to examine its accuracy and reliability. Differences and commonalities among the three methods were identified, particularly in terms of how qualitative and quantitative analyses are performed in each. Besides its potential usefulness as an aid for judicial decision-making, the checklist could be a valuable resource for training programs aimed at judges, as well as quality assurance programs.

The importance of forensic evidence for decisions on criminal guilt

Recent studies have found that the general public perceives forensic evidence to be relatively inaccurate and to involve high levels of human judgement. This study examines how important the general public finds forensic evidence by comparing decisions on guilt and punishment in criminal cases that involve forensic versus eyewitness testimony evidence and examining whether a CSI effect exists. Specifically, this experimental survey study utilized a 2 (crime type: murder or rape) × 4 (evidence type: DNA, fingerprint, victim eyewitness testimony, or bystander eyewitness testimony) - 1 (no victim testimony for murder scenario) design, yielding seven vignettes scenarios to which participants were randomly assigned. Results indicate that forensic evidence was associated with more guilty verdicts and higher confidence in a guilty verdict. Forensic evidence did not change the expected sentence length and did not generally affect the ideal sentence length. However, for rape, respondents believed that the defendant should receive a longer sentence when forensic evidence was presented but forensic evidence did not alter likely sentence that respondents expected the defendant to receive. The results of this study did not support a CSI effect. Overall, this study suggests that forensic evidence - particularly DNA - has a stronger influence during the verdict stage than the sentencing stage.

Juror appraisals of forensic evidence: Effects of blind proficiency and cross-examination

Forensic testimony plays a crucial role in many criminal cases, with requests to crime laboratories steadily increasing. As part of efforts to improve the reliability of forensic evidence, scientific and policy groups increasingly recommend routine and blind proficiency tests of practitioners. What is not known is how doing so affects how lay jurors assess testimony by forensic practitioners in court. In Study 1, we recruited 1398 lay participants, recruited online using Qualtrics to create a sample representative of the U.S. population with respect to age, gender, income, race/ethnicity, and geographic region. Each read a mock criminal trial transcript in which a forensic examiner presented the central evidence. The low-proficiency forensic examiner elicited a lower conviction rate and less favorable impressions than the control, an examiner for which no proficiency information was disclosed. However, the high-proficiency examiner did not correspondingly elicit a higher conviction rate or more favorable impressions than the control. In Study 2, 1420 participants, similarly recruited using Qualtrics, received the same testimony, but for some conditions the examiner was cross-examined by a defense attorney. We find cross-examination significantly reduced guilty votes and examiner ratings for low-proficiency examiners. These results suggest that disclosing results of blind proficiency testing can inform jury decision-making, and further, that defense lawyering can make proficiency information particularly salient at a criminal trial.

The Impact of Evidence Type on Police Investigators’ Perceptions of Suspect Culpability and Evidence Reliability

Abstract. In a repeated-measures experimental study, we examined how evidence type influences police investigators’ beliefs about (a) suspect’s culpability and (b) reliability of incriminating evidence. South Korean detectives ( N = 202) read four crime reports including general information about a crime and a suspect. In the general case information, one piece of critical and several pieces of noncritical evidence collected during the investigation were presented. Officers read four simulated reports of crimes, and in each report, they were given one piece of evidence linking the suspect to the crime. We manipulated the critical evidence identifying the suspect with four evidence types: CCTV, DNA, fingerprint, and eyewitness testimony. We found that evidence type influenced detectives’ judgments about suspect’s culpability and evidence reliability, such that when eyewitness (vs. CCTV, DNA, fingerprint) evidence was given as critical evidence, officers were more likely to think that the suspect was less culpable and that the evidence was less reliable. Theoretical and legal implications of these results are discussed.