| Literature DB >> 35243284 |
Adele Quigley-McBride1, Itiel E Dror2, Tiffany Roy3, Brandon L Garrett1, Jeff Kukucka4.
Abstract
Forensic analysts often receive information from a multitude of sources. Empirical work clearly demonstrates that biasing information can affect analysts' decisions, and that the order in which task-relevant information is received impacts human cognition and decision-making. Linear Sequential Unmasking (LSU; Dror et al., 2015) and LSU-Expanded (LSU-E; Dror & Kukucka, 2021) are examples of research-based procedural frameworks to guide laboratories' and analysts' consideration and evaluation of case information. These frameworks identify parameters-such as objectivity, relevance, and biasing power-to prioritize and optimally sequence information for forensic analyses. Moreover, the LSU-E framework can be practically incorporated into any forensic discipline to improve decision quality by increasing the repeatability, reproducibility, and transparency of forensic analysts' decisions, as well as reduce bias. Future implementation of LSU and LSU-E in actual forensic casework can be facilitated by concrete guidance. We present here a practical worksheet designed to bridge the gap between research and practice by facilitating the implementation of LSU-E.Entities:
Keywords: Cognitive bias; Confirmation bias; Contextual information; Decision-making; Forensic analysis; Linear Sequential Unmasking (LSU); Scientific evidence
Year: 2022 PMID: 35243284 PMCID: PMC8866671 DOI: 10.1016/j.fsisyn.2022.100216
Source DB: PubMed Journal: Forensic Sci Int Synerg ISSN: 2589-871X
Fig. 1Eight sources of cognitive bias in forensic science (Dror, 2020 [5]).
Ratings of the biasing potential, subjectivity, and irrelevance of “Case Information” (Fig. 1, Level 3) from empirical studies addressing contextual bias in forensic disciplines.
| Contextual information | LSU-E Ratings | Technique, participant sample, and citation | Notes and caveats |
|---|---|---|---|
| Another examiner's (or peer's) decision about the same materials. | Biasing power: 4 | The opinion or reputation of prior examiner might matter for ratings of biasing potential and subjectivity. | |
| Explicit suggestion about what the conclusion should be/which person left the sample at the crime scene. | Biasing power: 4 | If the nature of the crime, how the crime was committed, or the type of crime is revealed to analysts, this will increase the biasing power of the contextual information. | |
| The suspect provided a verified alibi. | Biasing power: 4 | The strength and the nature of the alibi will matter for ratings of biasing power and subjectivity. | |
| The suspect confessed to the crime. | Biasing power: 5 | ||
| Information about the type of crime/photos of the crime scene or relevant to the crime type | Biasing power: 4 | The relevance of this type of information will depend on the forensic discipline – very relevant to bloodstain pattern analysts, but not for fingerprint analysts. | |
| Demographic or background information about the victim or suspect (e.g., age, race, occupation, criminal history). | Biasing power: 4 | ||
| Examiner was exposed to/allowed access to other materials or forensic evidence they were not tasked with analyzing. | Biasing power: 5 | Subjectivity may vary based on the type of evidence or materials the analyst is exposed to, and whether they have access to the report or just the ultimate conclusion. | |
Notes. More details about each study, the type of information given to analysts in the study and how it was manipulated, the results, and a full list of references can be found on Open Science Framework.1 These studies all demonstrated the effect of information that falls within the third level of information that can influence analysts, as defined by Dror [5] and Fig. 1.
Ratings of the biasing potential, subjectivity, and irrelevance of different levels of information available to forensic analysts based on empirical tests of these types of information.
| Source of Bias ( | Contextual information | LSU-E Ratings | Technique, participant sample, and citation | Notes and caveats |
|---|---|---|---|---|
| Level 1 – “Data” | The sample obtained from the crime scene to be evaluated by the forensic analyst. | Biasing power: 1 | Subjectivity will vary based on the quality of the sample. A poor-quality sample with lots of information loss could be rated 5, but a pristine sample should be rated a 1 or 2. | |
| Level 2 – “Reference Materials” | Comparing the crime scene sample to suspect sample is inherently suggestive (bias). Evidence lineups reduce inherent bias in this standard analytic procedure (less bias). | Biasing power: 4 | Biasing power may be reduced if the crime scene sample is analyzed and documented prior to exposure to the reference material. | |
| Crime scene and suspect sample compared alone (bias) or with a non-matching sample as a reference (less bias). | Biasing power: 4 | |||
| Non-blind procedure (forensic expert knows the answer/location). | Biasing power: 4 | Ground truth is unknown, but analysts might form a belief about what ground truth is likely to be after exposure to other case information (+2 subjectivity/irrelevance in the real world). | ||
| Automated Fingerprint Identification System (AFIS) search information, rankings, and output. | Biasing power: 4 | Has not been tested, but these results likely extend to CODIS output and other software used by forensic scientists. | ||
| Level 4 – “Base Rates” | Past results from previous ‘similar’ cases. | Biasing power: 4 | Biasing potential would be lower (1 or 2) for situations where the base rates are less extreme e.g., 60% and 40%. | |
| Levels 5 and 6 - “Organizational Factors” and “Training and Motivation” | Analyst's knowledge about which side (prosecution or defense) hired them to testify. | Biasing power: 4 | This is called “adversarial allegiance” in the literature. | |
| Knowing that the results of your analysis are key to a person's case. | Biasing power: 5 | |||
| Levels 7 and 8 - “Personal Factors” and “Cognitive Architecture” | Pre-existing beliefs about a suspect's guilt, or personal history. | Biasing power: 4 | Police are not usually forensic scientists but do interpret forensic evidence and direct investigations that result in forensic samples. Pre-existing beliefs are fixed (low subjectivity) but are irrelevant. |
Notes. More details about each study, the type of information given to analysts in the study and how it was manipulated, the results, and a full list of references can be found on Open Science Framework.1 These studies all demonstrated the effect of information that falls within the level of information that can influence analysts—labelled in the far-left column—as defined by Dror [5] and Fig. 1.