Perceptions of blind proficiency testing among latent print examiners.

In recent years, scholars have levied multiple criticisms against traditional proficiency testing procedures in forensic laboratories. Consequently, on several occasions, authorities have formally recommended that laboratories implement blind proficiency testing procedures. Implementation has been slow, but laboratory management has increasingly expressed interest in initiating blind testing in at least some forensic disciplines, with some laboratories conducting blind testing in almost all disciplines. However, little is known about how a key population perceives blind proficiency testing, i.e., forensic examiners. We surveyed active latent print examiners (N = 338) to explore perceptions of blind proficiency testing and determine whether beliefs varied between examiners who work for laboratories with and without blind proficiency testing. Results suggest that examiners do not hold particularly strong beliefs about such procedures, but that examiners who work in laboratories with blind proficiency testing procedures view them significantly more positively than those who do not. Further, examiner responses provide insight into potential obstacles to continued implementation.

What types of information can and do latent print examiners review? A survey of practicing examiners.

Understanding typical work practices is important to understanding the decision-making process underlying latent print comparison and improving the reliability of the discipline. Despite efforts to standardize work practices, a growing literature has demonstrated that contextual effects can influence every aspect of the analytic process. However, very little is known about what types of information are available to latent print examiners, and what types of information latent print examiners routinely review. We surveyed practicing latent print examiners (N = 284) regarding what types of information are accessible during routine casework, and what types of information they routinely review during casework. We also explored whether access and inclination to review different types of information vary according to unit size and examiner role. Results indicated that information describing the physical evidence is accessible by almost all examiners (94.4%), and most examiners have access to offense type (90.5%), method of evidence collection (77.8%), and the names of both suspect (76.1%) and victim (73.9%). However, evidence description (86.3%) and method of evidence collection (68.3%) were the only information types consistently reviewed by most examiners. Findings also indicate that examiners in smaller laboratories have access to more information types and often review more information types than examiners from larger laboratories, but both populations choose to not review information at similar rates. Further, examiners in supervisory positions are more likely to choose to not review information than examiners in non-supervisory positions. Although there is some consensus regarding what types of information examiners routinely review, findings suggest that there is little absolute consensus regarding what information examiners can even access, and highlight two sources of variability in examiner work practices: employment setting and examiner role. This is concerning in light of efforts to maximize the reliability of analytic procedures (and ultimately, conclusions) and represents an important area of future study as the field progresses.

Does image editing improve the quality of latent prints? An analysis of image-editing techniques in one crime laboratory.

Field research within latent print comparison has remained sparse in the context of an otherwise growing body of literature examining the discipline. Studies examining how ACE-V procedures are implemented within active crime laboratories are especially lacking in light of research suggesting significant variability in examiner practices despite standardized ACE-V procedures. To date, no studies have examined a potentially important aspect of the Analysis phase: digital image editing. We provide information on the prevalence and types of latent print image editing within one laboratory (i.e., Houston Forensic Science Center), examine the potential effect of image editing on objective print quality and clarity (i.e., LQMetrics scores), and explore potential examiner differences in editing effectiveness. Results indicate that most latent prints are edited in some manner, and that image editing improves the quality and clarity of print images as defined by an objective quality metric, although examiners varied in their ability to improve the clarity of print images. Findings suggest that formal guidance or documentation of standard editing procedures would likely improve the reliability of examiner conclusions early in the latent print comparison process.

Blind testing in firearms: Preliminary results from a blind quality control program.

Open proficiency tests meet accreditation requirements and measure examiner competence but may not represent actual casework. In December 2015, the Houston Forensic Science Center began a blind quality control program in firearms examination. Mock cases are created to mimic routine casework so that examiners are unaware they are being tested. Once the blind case is assigned to an examiner, the evidence undergoes microscopic examination and comparison to determine whether the fired evidence submitted was fired in the same firearm. Fifty-one firearms blind cases resulting in 570 analysis and comparison determinations were reported between December 2015 and June 2021. No unsatisfactory results were obtained; however, 40.3% of comparisons in which the ground truth was either elimination or identification resulted in inconclusive conclusions. Due to the quality of some of the evidence submitted, inconclusive results were not unexpected. A ground truth of elimination and comparison result of inconclusive was observed at a rate of 74%, while a ground truth of identification and comparison result of inconclusive was observed at a rate of 31%. Bullets (61.8%) were the main contributors to inconclusive conclusions; variables such as the assigned examiners, training program, examiner experience, and the intended complexity of the case did not significantly contribute to the results. The program demonstrates that the quality management system and firearms section procedures can obtain accurate and reliable results and provides examiners added confidence in court. Additionally, the program can be tailored to target specific research questions and provide opportunities for collaboration with other laboratories and researchers.

Latent print quality in blind proficiency testing: Using quality metrics to examine laboratory performance.

Calls for blind proficiency testing in forensic science disciplines intensified following the 2009 National Academy of Sciences report and were echoed in the 2016 report by the President's Council of Advisors on Science and Technology. Both practitioners and scholars have noted that "open" proficiency tests, in which analysts know they are being tested, allow for test-taking behavior that is not representative of behavior in routine casework. This study reports the outcomes of one laboratory's blind quality control (BQC) program. Specifically, we describe results from approximately 2.5 years of blind cases in the latent print section (N = 376 latent prints submitted as part of 144 cases). We also used a widely available quality metrics software (LQMetrics) to explore relationships between objective print quality and case outcomes. Results revealed that nearly all BQC prints (92.0%) were of sufficient quality to enter into AFIS. When prints had a source present in AFIS, 41.7% of print searches resulted in a candidate list containing the true source. Examiners committed no false positive errors but other types of errors were more common. Average print quality was in the midpoint of the range (53.4 on a 0-to-100 scale), though prints were evenly distributed across the Good, Bad, and Ugly categories. Quality metrics were significantly associated with sufficiency determinations, examiner conclusions, and examiner accuracy. Implications for blind testing and the use of quality metrics in routine casework as well as proficiency testing are discussed.

Latent print comparison and examiner conclusions: A field analysis of case processing in one crime laboratory.

Scholarship on the latent print comparison process has expanded in recent years, responsive to the call for rigorous research by scholarly groups (e.g., National Academy of Sciences, 2009; President's Council of Advisors on Science and Technology, 2016). Important to the task of ultimately improving accuracy, consistency, and efficiency in the field is understanding different workflows and case outcomes. The current study describes the casework completed by a latent print unit in a large laboratory during one calendar year (2018), including a unique workflow that involves Preliminary AFIS Associations reported out as investigative leads. Approximately 45% of all examined prints were deemed to be of sufficient quality to enter into AFIS, and 22% of AFIS entries resulted in potential identifications. But examiner conclusions and AFIS outcomes (across three AFIS databases) varied according to case details, print source, and AFIS database. Moreover, examiners differed in case processing, sufficiency determinations, and AFIS conclusions. Results are discussed with respect to implications for future research (e.g., comparing these data to case processing data for other laboratories) and ultimately improving the practice of latent print examination.

Implementation of a Blind Quality Control Program in a Forensic Laboratory.

A blind quality control (QC) program was successfully developed and implemented in the Toxicology, Seized Drugs, Firearms, Latent Prints (Processing and Comparison), Forensic Biology, and Multimedia (Digital and Audio/Video) sections at the Houston Forensic Science Center (HFSC). The program was put into practice based on recommendations set forth in the 2009 National Academy of Sciences report and is conducted in addition to accreditation required annual proficiency tests. The blind QC program allows HFSC to test its entire quality management system and provides a real-time assessment of the laboratory's proficiency. To ensure the blind QC cases mimicked real casework, the workflow for each forensic discipline and their evidence submission processes were assessed prior to implementation. Samples are created and submitted by the HFSC Quality Division to whom the expected answer is known. Results from 2015 to 2018 show that of the 973 blind samples submitted, 901 were completed, and only 51 were discovered by analysts as being blind QC cases. Implementation data suggests that this type of program can be employed at other forensic laboratories.

Implementation of a Blind Quality Control Program in Blood Alcohol Analysis.

Declared proficiency tests are limited in their use for testing the performance of the entire system, because analysts are aware that they are being tested. A blind quality control (BQC) is intended to appear as a real case to the analyst to remove any intentional or subconscious bias. A BQC program allows a real-time assessment of the laboratory's policies and procedures and monitors reliability of casework. In September 2015, the Houston Forensic Science Center (HFSC) began a BQC program in blood alcohol analysis. Between September 2015 and July 2018, HFSC submitted 317 blind cases: 89 negative samples and 228 positive samples at five target concentrations (0.08, 0.15, 0.16, 0.20 and 0.25 g/100 mL; theoretical targets). These blood samples were analyzed by a headspace gas chromatograph interfaced with dual-flame ionization detectors (HS-GC-FID). All negative samples produced `no ethanol detected' results. The mean (range) of reported blood alcohol concentrations (BACs) for the aforementioned target concentrations was 0.075 (0.073-0.078), 0.144 (0.140-0.148), 0.157 (0.155-0.160), 0.195 (0.192-0.200) and 0.249 (0.242-0.258) g/100 mL, respectively. The average BAC percent differences from the target for the positive blind cases ranged from -0.4 to -6.3%, within our uncertainty of measurement (8.95-9.18%). The rate of alcohol evaporation/degradation was determined negligible. A multiple linear regression analysis was performed to compare the % difference in BAC among five target concentrations, eight analysts, three HS-GC-FID instruments and two pipettes. The variables other than target concentrations showed no significant difference (P > 0.2). While the 0.08 g/100 mL target showed a significantly larger % difference than higher target concentrations (0.15-0.25 g/100 mL), the % differences among the higher targets were not concentration-dependent. Despite difficulties like gaining buy-in from stakeholders and mimicking evidence samples, the implementation of a BQC program has improved processes, shown methods are reliable and added confidence to staff's testimony in court.