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Abstract
Forensic science is routinely used in the service of the United States’ criminal legal system. In such cases, lawyers, judges, and jurors each have distinct competencies. Trial judges must determine the admissibility of expert evidence and deliver jury instructions; lawyers must select, present, and challenge the evidence; and jurors must determine the weight of the evidence. As they discharge these competencies, each agent might need to engage with the often unfamiliar methods introduced and discussed by a forensic science expert. These activities represent an intersection between law and science—two culturally divergent disciplines—where it is recognized science literacy—“the disposition and knowledge needed to engage with science”—for legal professionals and jurors is important to serving justice. There are limitations, however, in the current provision for supporting legal professionals to develop their science literacy, which is foundational to optimizing the carrying out of juror competencies. Despite this, the criminal legal system is organized in such a way as to routinely defer to the decision-making competencies of lawyers, judges, and jurors. Through a content analysis of case law referencing the National Academy of Sciences’ (NAS) forensic science report portfolio in criminal proceedings—which is positioned as a case study—this paper demonstrates how this systemic practice—driven by the legal system’s fidelity to factors associated with the legal process vision—should motivate stakeholders to prioritize delivery of a meaningful science literacy provision for lawyers. Part I broadly outlines the roles of lawyers, judges, and jurors in criminal legal proceedings involving forensic science evidence, explaining this interaction as an intersection of law and science. Part II describes our research design, including the rationale for selecting case law referencing the NAS’ forensic science report portfolio as a case study. Part III presents our findings in three thematic areas: (1) deference to lawyers’ strategic decisions, particularly in the context of cross-examination; (2) deference to the gatekeeping function of trial judges and the role of precedent; and (3) deference to the jury’s fact-finding role. It concludes that these findings, coupled with the reality that an institutional overhaul is unlikely, should focus minds on supporting—as a priority—lawyers to develop their science literacy, and that conceptualizing ‘science literacy’ for lawyers is a necessary step in moving towards that goal.
Introduction
Forensic science evidence is used “routinely in the service of the criminal justice system”[1] and has “long been at the forefront in answering complicated questions brought before the bar of justice.”[2] In such cases, judges, lawyers, and jurors each have distinct competencies. Trial judges must determine the admissibility of expert evidence and deliver jury instructions; lawyers must select, present, and challenge the evidence; and jurors must determine the weight of the evidence.[3]
However, there is limited education and training for these key agents with respect to supporting them to evaluate forensic science evidence,[4] a situation recognized by the National Academy of Sciences (“NAS”), the United States’ premier scientific think tank. Since the early 1990s, following the introduction of DNA technology within the criminal legal system, the NAS has reported on various forensic disciplines—including DNA, polygraph, ballistics, fingerprint, and bite-mark evidence—parallel to (and sometimes motivated by) growing interest in their reliability.[5] Following a critical appraisal of the entire field,[6] in 2009 the NAS recommended that Congress establish an independent oversight body to monitor the implementation of its recommendations,[7] which included support measures for lawyers, judges, and jurors.[8] A comprehensive support package, however, has not fully emerged. Yet, the need for one remains. This is because the criminal legal system is organized in such a way as to routinely defer to the decision-making competencies of these agents, and that configuration is unlikely to change.
Through a content analysis of case law, this paper posits this organizational practice is driven by—as suggested previously—the criminal legal system’s fidelity to factors associated with the legal process vision.[9] Part I broadly outlines key competencies of lawyers, judges and jurors in criminal legal proceedings involving forensic science evidence, explaining them as an intersection of two culturally divergent disciplines: law and science. Part II describes our research design, which used case law referencing the NAS’ forensic science report portfolio as a case study. Part III presents our findings in three thematic areas: (1) deference to lawyers’ strategic decisions, particularly in the context of cross-examination; (2) deference to the gatekeeping function of trial judges and the role of precedent; and (3) deference to the jury’s fact-finding role. It concludes that these findings, coupled with the reality that an institutional overhaul is unlikely, should focus minds on the need to develop an appropriate education and training support package for lawyers, as a priority group. We suggest that conceptualizing ‘science (or scientific) literacy’—“the disposition and knowledge needed to engage with science”[10] —for lawyers is a necessary step in moving towards this goal and offer the criminal legal system’s consumption of forensic science as a possible exploratory case study.
I. Competencies and Cultural Differences
In criminal proceedings involving expert forensic science evidence, lawyers, judges, and jurors have distinct competencies that can be described in a broad sequence.
Lawyers, in line with their monopoly on determining case strategy, must first decide whether to include expert evidence within their case. Lawyers will call upon experts that have “scientific, technical, or other specialized knowledge”[11] capable of assisting the fact finder to understand the evidence in a case and/or to resolve a contentious fact. For example, a lawyer might need a firearms examiner to compare ammunition found at a crime scene to ammunition test fired from a client’s firearm. Applying the “reliable principles and methods”[12] of their discipline (for example, the discipline of firearms identification) to the case facts, experts are expected to use their experience and training to testify to opinions (for example, whether the defendant’s firearm discharged suspect ammunition) based on “sufficient facts and data.”[13]
Trial judges are tasked with safeguarding this expectation. In overseeing evidentiary and in limine hearings, they must make admissibility decisions that ensure only relevant and reliable expert evidence is admitted in proceedings. In so deciding, they generally consider whether a method can or has been tested; has a known or potential error rate; has been subject to peer review; has standards controlling its operation; and is generally accepted within the relevant scientific community.[14] If expert evidence is deemed admissible, lawyers will, through their oversight of direct-examination, shape how it is presented on behalf of their party at trial. They will design questions to elicit an expert’s qualifications, experience, methods, and findings (for example, how a firearms examiner made the comparison between suspect and test-fired ammunition). In controlling cross-examination, lawyers also shape how opposing expert evidence is challenged by designing questions that, for instance, highlight limitations in an opposing expert’s methods and findings (for example, limitations associated with expert subjectivity).
In their role as fact finders, jurors are then charged with weighing the probative value of expert evidence alongside all other evidence presented. Trial judges may provide jury instructions to inform this task. Model instructions typically remind jurors about the witness’s expertise, that they can afford as much weight (including no weight) to the expert’s testimony, and what factors they may take into consideration, such as the expert’s qualifications and the reliability of the information underpinning the expert’s opinion.[15] Jurors then determine a verdict.
Finally, if a defendant is convicted, a lawyer may later bring appeal proceedings, which could involve claims that a lawyer, judge, and/or jury discharged competencies improperly.
A. Law & Science
The above sequence represents an intersection between two culturally divergent disciplines: law and science, a relationship that has been described as “an uneasy alliance.”[16] The two disciplines can be “strange partners”[17] given their different approaches to the world.[18] These differences present “both systemic and pragmatic dilemmas for the law and the actors within it.”[19] These dilemmas include knowledge gaps of various shapes. Legal education has been described as a “black hole” for STEM education,[20] leading to judges and lawyers “generally lack[ing] the scientific expertise necessary to comprehend and evaluate forensic evidence in an informed manner.”[21] Similar concerns exist about jurors.[22] At the same time, there remains much to determine within individual forensic disciplines, especially with regards to scientific validity:
The simple reality is that the interpretation of forensic evidence is not always based on scientific studies to determine its validity. This is a serious problem. Although research has been done in some disciplines, there is a notable dearth of peer-reviewed, published studies establishing the scientific bases and validity of many forensic methods.[23]
The adversarial system can exacerbate these gaps. Adversarial practices can improperly polarize forensic science evidence—“information that reaches the legal system does not represent the scientific field more generally”[24]—and can blur reality, with “[jurors] hear[ing] highly practiced alternative stories that only roughly approximate what might be termed reality.”[25] Experts at the “margins of their disciplines”[26] can be “chosen . . . because they are willing to be . . . more certain of their conclusions.”[27] In fact, Jennifer Laurin asserts that the “criminal justice system does far too little to grapple with the implications of scientific change for its truth-finding functions.”[28]
The criminal legal system has been particularly struggling with these knowledge gaps relating to forensic science since the introduction of DNA evidence in the 1980s.[29] This is not surprising. When science progresses, challenges can often emerge in law. The law “will always lag behind the sciences to some degree because of the need for solid scientific consensus before the law incorporates its teachings.”[30] As Laurin describes, “Law cannot, of course, fully bend to science’s pace and manner of truth production.”[31] Yet, as Thomas D. Albright and Brandon L. Garrett suggest,
The “law incorporating the teachings” of science should not remain static. “The law” need not wait for “finished” science, either…. law should use standards sufficiently flexible to incorporate an evolving scientific understanding of the world in which we live.[32]
As agents of the law, lawyers, judges, and jurors are key to properly incorporating the teachings of science into the criminal legal system. Developing a deeper understanding of their competencies in cases involving scientific evidence, including forensic science, is therefore instructive to finding out what support they need to properly discharge their competencies.
[1] The Comm. on Identifying the Needs of the Forensic Sci. Cmty., Nat'l Rsch. Council of the Nat'l Acads., Strengthening the Forensic Sciences in the United States: A Path Forward 9 (The Nat’l Acads. Press 2009) [hereinafter Strengthening].
[2] Matthew F. Redle & Hon. Christopher J. Plourd, A Path Forward: The Value of Forensic Science Standards Development and Use to the American Legal System, 35 Crim. Just. 61 (2020).
[3] Obviously, many more agents are involved in criminal proceedings, and experts are particularly relevant to the competencies summarized in this opening paragraph. The focus of this paper, however, is on specific competencies of lawyers, judges, and jurors i.e., non-experts in a scientific sense.
[4] See Strengthening, supra note 1, at 26–28 (summarizing the Committee’s findings regarding “Insufficient Education and Training”).
[5] See Amelia Shooter & Sarah L. Cooper, A Template for Enhancing the Impact of the National Academy of Sciences’ Reporting on Forensic Science, 8 Br. J. Am. Leg. Studies (Special Issue) 443 (2019).
[6] Strengthening, supra note 1 at xix (“Recognizing that significant improvements are needed in forensic science, Congress directed the National Academy of Sciences to undertake the study that led to this report. . . . In adopting this report, the aim of our committee is to chart an agenda for progress in the forensic science community and its scientific disciplines.”).
[7] Id. at 80–83.
[8] Id. at 26–28.
[9] See, e.g., Shooter & Cooper, supra note 5, at 462; Sarah Lucy Cooper, Judicial Responses to Shifting Scientific Opinion in Forensic Identification Evidence and Newly Discovered Evidence Claims in the United States: The Influence of Finality and Legal Process Theory, 4 Br. J. Am. Leg. Studies 649 (2015); Sarah Lucy Cooper, Judicial Responses to Challenges to Firearms-Identification Evidence: A Need for New Judicial Perspectives on Finality, 31 T.M. Cooley L. Rev. 457 (2014).
[10] Comm. on Science Literacy and Pub. Perception of Science, Science Literacy: Concepts, Contexts, and Consequences 27 (Nat’l Acads. Press 2016) [hereinafter Science Literacy].
[11] Fed. R. Evid. 702. The federal framework is provided by way of a general example.
[12] Id.
[13] Id.
[14] Daubert v. Merrell Dow Pharms., Inc., 509 U.S. 579, 591–94 (1993); Clifford S. Fishman & Anne Toomey McKenna, Jones on Evidence § 45:5 (7th ed. 2022) (“Although Daubert is only binding on federal courts, many states have expressly adopted its standard or apply the Daubert factors in interpreting their own rules of evidence. Some states continue to follow Frye while others apply their own, separate framework or a hybrid approach.”).
[15] See, e.g., 8th Cir. Model Crim. Jury Instr. § 4.10, at 104 (2021) (“You have heard testimony from persons described as experts. Persons who, by knowledge, skill, training, education or experience, have become expert in some field may state their opinions on matters in that field and may also state the reasons for their opinion. Expert testimony should be considered just like any other testimony. You may accept or reject it, and give it as much weight as you think it deserves, considering the witness' education and experience, the soundness of the reasons given for the opinion, the acceptability of the methods used, and all the other evidence in the case.”).
[16] Strengthening, supra note 1, at 86.
[17] Redle & Plourd, supra note 2, at 61.
[18] Id. (“Science is an empirical method of learning anchored to the principals of observation and discovery as to how the natural world works. Scientific knowledge advances human understanding by developing experiments that provide the scientist with an objective answer to the question presented. Through a scientific method of study, a scientist systematically observes physical evidence and methodically records the data that support the scientific process. The law, on the other hand, starts out with at least two competing parties who use the courthouse as a battleground to resolve factual issues within the context of constitutional, statutory, and decisional law. In science, all answers are provisional, while the law seeks finality.”); David L. Faigman, Legal Alchemy: The Use and Misuse of Science in the Law 56 (W.H. Freeman & Co., 1999) (“Science progresses while law builds slowly on precedent. Science assumes that humankind is determined by some combination of nature and nurture, while law assumes that humankind can transcend these influences and exercise free will. Science is a cooperative endeavor, while most legal institutions operate on an adversary model.”); M.A. Berger and L.M. Solan, The Uneasy Relationship Between Science and Law: An Essay and Introduction, 73 Brook. L. Rev. 847 (2008).
[19] Developments in the Law—Confronting the New Challenges of Scientific Evidence, 108 Harv. L. Rev. 1481, 1484 (1995) [hereinafter Confronting the New Challenges of Scientific Evidence].
[20] Jessica D. Gabel, Forensiphilia: Is Public Fascination with Forensic Science A Love Affair or Fatal Attraction?, 36 New Eng. J. on Crim. & Civ. Confinement 233, 255–58 (2010).
[21] Strengthening, supra note 1, at 110.
[22] Id. at 236–37; Sarah Lucy Cooper, Challenges to Fingerprint Identification Evidence: Why the Courts Need A New Approach to Finality, 42 Mitchell Hamline L. Rev. 785–89 (2016) [hereinafter Challenges to Fingerprint Identification Evidence]. It is also recognised that forensic examiners require up-skilling. See Strengthening, supra note 1, at 238 (“Forensic science examiners need additional training in the principles, practices, and contexts of scientific methodology, as well as in the distinctive features of their specialty.”).
[23] Strengthening, supra note 1, at 8. For a recent account, see Maneka Sinha, Radically Reimagining Forensic Evidence, 73 Ala. L. Rev. 879 (2022).
[24] Faigman, supra note 18, at 54.
[25] Id. at 65.
[26] Id. at 54.
[27] Id.
[28] Jennifer E. Laurin, Criminal Law’s Science Lag: How Criminal Justice Meets Changed Scientific Understanding, 93 Tex. L. Rev. 1751, 1753 (2015).
[29] Strengthening, supra note 1, at 40 (“In the 1980s, the opportunity to use the techniques of DNA technologies to identify individuals for forensic and other purposes became apparent.”).
[30] Brodes v. State, 614 S.E.2d 766, 771 (Ga. 2005) (quoting State v. Long, 721 P.2d 483, 491 (Utah 1986)).
[31] Laurin, supra note 28, at 1753.
[32] Thomas D. Albright & Brandon L. Garrett, The Law and Science of Eyewitness Evidence, 102 B.U. L. Rev. 511, 578 (2022).