Evidence Commons^™

Proving The Future In Criminal Cases, Christopher Slobogin

Vanderbilt Law School Faculty Publications

Expert opinion about dangerousness—the risk of reoffending—is commonly introduced at sentencing, criminal commitment proceedings, and some types of pretrial detention hearings. This Essay argues that the rules governing the admissibility of scientific evidence should apply to this testimony and that, on that assumption, such evidence must be (1) “material” (logically relevant, empirically generalizable, and epistemologically germane), (2) “probative” (a measure of accuracy, which is more stringent when the evidence is from an expert), (3) helpful to the factfinder (through promoting “incremental validity”), and (4) presented in a non-prejudicial manner (i.e., in a way that minimizes the possibility it will be …

The Needless Search For A Founding-Era "Hearsay" Definition, Jeffrey Bellin

Vanderbilt Law School Faculty Publications

Modern Confrontation Clause doctrine permits only unconfronted "out-of-court statements that would have been admissible in a criminal case at the time of the founding." To operationalize this concept, the Supreme Court identifies "testimonial hearsay" as the Clause's primary concern. Its opinions regularly dive into the historical record to refine what counts as "testimonial" but ignore that record in defining "hearsay." This omission cannot last. Cases in the lower courts, and one on the Court's recent docket, concern testimonial but (arguably) non-hearsay statements. And while confrontation jurisprudence is supposed to be tied to founding-era evidence law, the "hearsay" definition, casually referenced …

Sentencing In An Era Of Plea Bargains, Jeffrey Bellin, Jeenia I. Turner

Vanderbilt Law School Faculty Publications

The literature offers inconsistent answers to a question that is foundational to criminal law: Who imposes sentences? Traditional narratives place sentencing responsibility in the hands of the judge. Yet, in a country where 95% of criminal convictions come from guilty pleas (not trials), modern American scholars center prosecutors who control plea terms as the deciders of punishment. This Article highlights and seeks to resolve the tension between these conflicting narratives by charting the pathways by which sentences are determined in a system dominated by plea bargains. After reviewing the empirical literature on sentence variation, examining state and federal plea-bargaining rules …

Symposium: Reimagining The Rules Of Evidence At 50, Edward K. Cheng

Vanderbilt Law School Faculty Publications

Prior to the eighteenth century, cartographers would often fill uncharted areas of maps with sea monsters, other artwork, or even rank speculation—a phenomenon labeled “horror vacui,” or fear of empty spaces. For example, in Paolo Forlani’s world map of 1565, a yet to-be-discovered southern continent was depicted with anticipated mountain chains and animals. The possible explanations for horror vacui are varied, but one reason may have been a desire “to hide [the mapmakers’] ignorance.” Not until “maps began to be thought of as more purely scientific instruments . . . [did] cartographers . . . restrain their concern about spaces …

Bending The Rules Of Evidence, Edward K. Cheng, G. Alexander Nunn, Julia Simon-Kerr

Vanderbilt Law School Faculty Publications

The evidence rules have well-established, standard textual meanings—meanings that evidence professors teach their law students every year. Yet, despite the rules’ clarity, courts misapply them across a wide array of cases: Judges allow past acts to bypass the propensity prohibition, squeeze hearsay into facially inapplicable exceptions, and poke holes in supposedly ironclad privileges. And that’s just the beginning.

The evidence literature sees these misapplications as mistakes by inept trial judges. This Article takes a very different view. These “mistakes” are often not mistakes at all, but rather instances in which courts are intentionally bending the rules of evidence. Codified evidentiary …

Embracing Deference, Edward K. Cheng, Elodie O. Currier, Payton B. Hampton

Vanderbilt Law School Faculty Publications

A fundamental conceptual problem has long dogged discussions about scientific and other expert evidence in the courtroom. In American law, the problem was most famously posed by Judge Learned Hand, who asked: "[H]ow can the jury judge between two statements each founded upon an experience confessedly foreign in kind to their own? It is just because they are incompetent for such a task that the expert is necessary at all." This puzzle, sometimes known as the "expert paradox," is quite general. It applies not only to the jury as factfinder, but also to the judge as gate- keeper under the …

The Consensus Rule: A New Approach To Scientific Evidence, Edward K. Cheng

Vanderbilt Law School Faculty Publications

Founded on good intentions but unrealistic expectations, the dominant Daubert framework for handling expert and scientific evidence should be scrapped. Daubert asks judges and jurors to make substantively expert determinations, a task they are epistemically incompetent to perform as laypersons. As an alternative, this Article proposes a new framework for handling expert evidence. It draws from the social and philosophical literature on expertise and begins with a basic question: How can laypersons make intelligent decisions about expert topics? From there, it builds its evidentiary approach, which ultimately results in an inference rule focused on expert communities. Specifically, when dealing with …

Completing The Quantum Of Evidence, Edward K. Cheng, Brooke Bowerman

Vanderbilt Law School Faculty Publications

In "Evidentiary Irony and the Incomplete Rule of Completeness," Professors Daniel Capra and Liesa Richter comprehensively catalog the many shortcomings in current Federal Rule of Evidence 106 and craft a compelling reform proposal. Their proposal admirably solves the identified problems, keeps the rule reasonably succinct, and furthers the accuracy and fairness goals of the rules of evidence. In this Response, we focus on Capra & Richter's proposal to formally recognize a "trumping" power in Rule 106, which would allow an adverse party to offer a completing statement even if it would be "otherwise inadmissible under the rule against hearsay."

Unraveling Williams V. Illinois, Edward K. Cheng, Cara C. Mannion

Vanderbilt Law School Faculty Publications

This Essay addresses one of the key evidentiary problems facing courts today: the treatment of forensic reports under the Confrontation Clause. Forensics are a staple of modern criminal trials, yet what restrictions the Confrontation Clause places on forensic reports is entirely unclear. The Supreme Court’s latest decision on the issue, Williams v. Illinois, sowed widespread confusion among lower courts and commentators, and during the 2018 Term, Justices Gorsuch and Kagan dissented to the denial of certiorari in Stuart v. Alabama, a case that would have revisited (and hopefully clarified) Williams.

Our Essay dispels the confusion in Williams v. Illinois. …

Conference On Best Practices For Managing Daubert Questions, Edward K. Cheng, D. J. Capra, Et Al

Vanderbilt Law School Faculty Publications

When we are talking about overstatement, is it so apparent that surely the jury could understand that? Or that on cross at trial, would the opposing counsel make that apparent so that the jury would deal with it on its own? Or is it overstatement, in ways that you normally see, in that it becomes opaque and therefore misleading to the jury and the jury would never be able to figure it out?

Beyond The Witness: Bringing A Process Perspective, Edward K. Cheng, G. Alexander Nunn

Vanderbilt Law School Faculty Publications

For centuries, the foundation of the Anglo-American trial has been the witness.' Witnesses report on their personal observations, provide opinions of character, offer scientific explanations, and in the case of parties, narrate their own story. Indeed, even for documentary and other physical evidence, witnesses often provide the conduit through which such evidence reaches the factfinder. Documentary or physical evidence rarely stands on its own. The law of evidence has thus unsurprisingly focused on-or perhaps obsessed over-witnesses. The hearsay rule and the Confrontation Clause demand that declarants be available witnesses at trial so that they may be subject to cross-examination.' Expert …

Policing The Admissibility Of Body Camera Evidence, Jeffrey Bellin, Shevarma Pemberton

Vanderbilt Law School Faculty Publications

Body cameras are sweeping the nation and becoming, along with the badge and gun, standard issue for police officers. These cameras are intended to ensure accountability for abusive police officers. But, if history is any guide, the videos they produce will more commonly be used to prosecute civilians than to document abuse. Further, knowing that the footage will be available as evidence, police officers have an incentive to narrate body camera videos with descriptive oral statements that support a later prosecution. Captured on an official record that exclusively documents the police officer's perspective, these statements-for example, "he just threw something …

Surprise Vs. Probability As A Metric For Proof, Edward K. Cheng, Matthew Ginther

Vanderbilt Law School Faculty Publications

In this Symposium issue celebrating his career, Professor Michael Risinger in Leveraging Surprise proposes using "the fundamental emotion of surprise" as a way of measuring belief for purposes of legal proof. More specifically, Professor Risinger argues that we should not conceive of the burden of proof in terms of probabilities such as 51%, 95%, or even "beyond a reasonable doubt." Rather, the legal system should reference the threshold using "words of estimative surprise" -asking jurors how surprised they would be if the fact in question were not true. Toward this goal (and being averse to cardinality), he suggests categories such …

Forensics, Chicken Soup, And Meteorites: A Tribute To Michael Risinger, Edward K. Cheng

Vanderbilt Law School Faculty Publications

Michael Risinger's scholarship has had a profound impact on our field. And while his work has run the gamut in evidence law, I think it is clear that Michael's true love has always been expert evidence, and more specifically, forensics. So let me take a moment to revisit "an oldie but a goodie": his 1989 article entitled Exorcism of Ignorance as a Proxy for Rational Knowledge: The Lessons of Handwriting Identification "Expertise," published in the University of Pennsylvania Law Review, and co-authored with Mark Denbeaux and Michael Saks.' For those of you who have not read the article, you should. …

Manipulation Of Suspects And Unrecorded Questioning, Christopher Slobogin

Vanderbilt Law School Faculty Publications

Fifty years after Miranda, courts still do not have clear guidance on the types oftechniques police may use during interrogation. While first-generation tactics (a.k.a. the third degree) are banned, second-generation tactics such as those found in the famous Reid Manual continue to be used by interrogators. The Supreme Court has sent only vague signals as to which of these second- generation techniques, if any, are impermissible, and has made no mention of newly developed third-generation tactics that are much less reliant on manipulation. This Article divides second-generation techniques into four categories: impersonation, rationalization, fabrication, and negotiation. After concluding, based on …

The Science Of Gatekeeping: Using The Structure Of Scientific Inference To Draw The Line Between Admissibility And Weight In Expert Testimony, Christopher Slobogin, David Faigman, John Monahan

Vanderbilt Law School Faculty Publications

Fundamental to all evidence rules is the division of responsibility between the judge, who determines the admissibility of evidence, and the jury, which gauges its weight. In most evidentiary contexts, such as those involving hearsay and character, threshold admissibility obligations are clear and relatively uncontroversial. The same is not true for scientific evidence. The complex nature of scientific inference, and in particular the challenges of reasoning from group data to individual cases, has bedeviled courts. As a result, courts vary considerably on how they define the judge's gatekeeping task under Federal Rule of Evidence 702 and its state equivalents.

This …

The Case For Ehearsay, Jeffrey Bellin

Vanderbilt Law School Faculty Publications

On April 4, 2014, the Advisory Committee for the Federal Rules of Evidence convened the Symposium on the Challenges of Electronic Evidence. The purpose of the symposium was "to consider the intersection of the evidence rules and emerging technologies" and explore what rule changes, if any, might be warranted in light of sweeping changes in the way people communicate.1 As an unapologetic advocate for changes to the hearsay rules, I thought it a happy coincidence that the symposium coincided with Seventh Circuit Judge Richard Posner's call for sweeping hearsay reform. In a 2013 article, eHearsay, I proposed a hearsay exception …

Presentation To The Advisory Committee On Evidence Rules, Jeffrey Bellin

Vanderbilt Law School Faculty Publications

JUDGE FITZWATER: Good morning, everyone. On behalf of Judge Jeffrey S. Sutton, and the members of the Committee on Rules of Practice and Procedure of the Judicial Conference of the United States, my colleagues on the Advisory Committee on Evidence Rules, and our Committee Reporter, Professor Dan Capra, welcome to the Symposium on the Challenges of Electronic Evidence. We are indebted to the University of Maine School of Law for its willingness to host this symposium, not once, but twice, because we were scheduled to hold the symposium last October before the government shutdown caused it to be cancelled. I …

Neuroscientists In Court, Owen D. Jones, Anthony D. Wagner, David L. Faigman, Marcus E. Raichle

Vanderbilt Law School Faculty Publications

Neuroscientific evidence is increasingly being offered in court cases. Consequently, the legal system needs neuroscientists to act as expert witnesses who can explain the limitations and interpretations of neuroscientific findings so that judges and jurors can make informed and appropriate inferences. The growing role of neuroscientists in court means that neuroscientists should be aware of important differences between the scientific and legal fields, and, especially, how scientific facts can be easily misunderstood by non-scientists,including judges and jurors.

This article describes similarities, as well as key differences, of legal and scientific cultures. And it explains six key principles about neuroscience that …

Group To Individual Inference In Scientific Expert Testimony, Christopher Slobogin, David Faigman, John Monahan

Vanderbilt Law School Faculty Publications

A fundamental divide exists between what scientists do as scientists and what courts often ask them to do as expert witnesses. Whereas scientists almost invariably inquire into phenomena at the group level, trial courts typically need to resolve cases at the individual level. In short, scientists generalize while courts particularize. A basic challenge for trial courts that rely on scientific experts, therefore, concerns determining whether and how scientific knowledge derived from studying groups can be helpful in the individual cases before them (what this Article refers to as "G2i'). To aid in dealing with this challenge, this Article proposes a …

Being Pragmatic About Forensic Linguistics, Edward K. Cheng

Vanderbilt Law School Faculty Publications

This article aims to provide some legal context to the Authorship Attribution Workshop (“conference”). In particular, I want to offer some pragmatic observations on what courts will likely demand of forensic linguistics experts and tentatively suggest what the field should aspire to in both the short and long run.

Reconceptualizing The Burden Of Proof, Edward K. Cheng

Vanderbilt Law School Faculty Publications

The preponderance standard is conventionally described as an absolute probability threshold of 0.5. This Essay argues that this absolute characterization of the burden of proof is wrong. Rather than focusing on an absolute threshold, the Essay reconceptualizes the preponderance standard as a probability ratio and shows how doing so eliminates many of the classical problems associated with probabilistic theories of evidence. Using probability ratios eliminates the so-called Conjunction Paradox, and developing the ratio tests under a Bayesian perspective further explains the Blue Bus problem and other puzzles surrounding statistical evidence. By harmonizing probabilistic theories of proof with recent critiques advocating …

Book Review: Burden Of Proof: A Review Of Math On Trial, Paul H. Edelman

Vanderbilt Law School Faculty Publications

In Math on Trial, Leila Schneps and Coralie Col­ mez write about the abuse of mathematical argu­ ments in criminal trials and how these flawed arguments "have sent innocent people to prison" (p. ix). Indeed, people "saw their lives ripped apart by simple mathematical errors." The purpose of focusing on these errors, despite mathematics' "relatively rare use in trials" (p. x), is "that many of the common mathematical fallacies that pervade the public sphere are perfectly represented by these trials. Thus they serve as ideal illustrations of these errors and of the drastic consequences that faulty reasoning has on real …

The Incredible Shrinking Confrontation Clause, Jeffrey Bellin

Vanderbilt Law School Faculty Publications

Sharp turns in the Supreme Court's recent Confrontation Clause jurisprudence have left scholars reeling from conflicting emotions: exhilaration, despair, denial, and soon, perhaps, cynical acceptance. While most commentators celebrated the demise of the incoherent Ohio v. Roberts framework, their excitement largely faded as the Court's decisions in Davis v. Washington and Bryant v. Michigan revealed nascent flaws in the evolving doctrine and sharply curtailed the newly revitalized confrontation right.

Recent scholarship strives to reanimate the jurisprudence by expanding the doctrinal definition of "testimonial" statements - the sole form of evidence Associate Professor, William & Mary Law School. I would like …

When 10 Trials Are Better Than 1000: An Evidentiary Perspective On Trial Sampling, Edward K. Cheng

Vanderbilt Law School Faculty Publications

In many mass tort cases, separately trying all individual claims is impractical, and thus a number of trial courts and commentators have explored the use of statistical sampling as a way of efficiently processing claims. Most discussions on the topic, however, implicitly assume that sampling is a “second best” solution: individual trials are preferred for accuracy, and sampling only justified under extraordinary circumstances. This Essay explores whether this assumption is really true. While intuitively one might think that individual trials would be more accurate at estimating liability than extrapolating from a subset of cases, the Essay offers three ways in …

Facebook, Twitter, And The Uncertain Future Of Present Sense Impressions, Jeffrey Bellin

Vanderbilt Law School Faculty Publications

The intricate legal framework governing the admission of out-of-court statements in American trials is premised on increasingly outdated communi- cation norms. Nowhere is this more apparent than with the hearsay exception for "present sense impressions." Changing communication practices typified by interactions on social media websites like Facebook and Twitter herald the arrival of a previously uncontemplated-and uniquely unreliable-breed of present sense impressions. This Article contends that the indiscriminate admission of these electronic present sense impressions (e-PSIs) is both normatively undesirable and inconsistent with the traditional rationale for the present sense impression exception. It proposes a reform to the exception that …

Erie And The Rules Of Evidence, Edward K. Cheng

Vanderbilt Law School Faculty Publications

Jay Tidmarsh offers an intriguing new test for drawing the allimportant line between procedure and substance for purposes of Erie. The Tidmarsh test is attractively simple, yet seemingly reaches the right result in separating out truly “procedural” rules from more substantive ones. Since I am not a proceduralist, in this Response I will leave the Tidmarsh test’s explanatory power and practical workability vis-à-vis general civil procedure rules to others more qualified than I. Instead, I want to focus on the implications of the Tidmarsh test for the Federal Rules of Evidence. Like others in the evidence world, I have long …

Brain Scans As Evidence: Truths, Proofs, Lies, And Lessons, Owen D. Jones, Francis X. Shen

Vanderbilt Law School Faculty Publications

This contribution to the Brain Sciences in the Courtroom Symposium identifies and discusses issues important to admissibility determinations when courts confront brain-scan evidence. Through the vehicle of the landmark 2010 federal criminal trial U.S. v. Semrau (which considered, for the first time, the admissibility of brain scans for lie detection purposes) this article highlights critical evidentiary issues involving: 1) experimental design; 2) ecological and external validity; 3) subject compliance with researcher instructions; 4) false positives; and 5) drawing inferences about individuals from group data. The article’s lessons are broadly applicable to the new wave of neurolaw cases now being seen …

Scientific Evidence As Foreign Law, Edward K. Cheng

Vanderbilt Law School Faculty Publications

Most contemporary debates about scientific evidence focus on admissibility under Daubert and the Federal Rules of Evidence. That bias is quite understandable-after all, it is the framework imposed by the United States Supreme Court. Daubert, however, rests on a fundamental assumption: that courts should treat scientific facts like any other adjudicative facts ultimately left to the jury. Perhaps the involvement of specialized knowledge requires judges to act as gatekeepers to ensure some basic level of reliability, but under Daubert, scientific facts are still just facts. As I will argue, scientific facts fit awkwardly into the conventional framework for conceptualizing and …

A Practical Solution To The Reference Class Problem, Edward K. Cheng

Vanderbilt Law School Faculty Publications

The "reference class problem" is a serious challenge to the use of statistical evidence that arguably arises every day in wide variety of cases, including toxic torts, property valuation, and even drug smuggling. At its core, it observes that statistical inferences depend critically on how people, events, or things are classified. As there is (purportedly) no principle for privileging certain categories over others, statistics become manipulable, undermining the very objectivity and certainty that make statistical evidence valuable and attractive to legal actors. In this paper, I propose a practical solution to the reference class problem by drawing on model selection …