Law Commons^™

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

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."

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?

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. …

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 …

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 …

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 …

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 …

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.

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 …

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 …

Will Quants Rule The (Legal) World?, Edward K. Cheng

Vanderbilt Law School Faculty Publications

Professor Ian Ayres, in his new book, Super Crunchers, details the brave new world of statistical prediction and how it has already begun to affect our lives. For years, academic researchers have known about the considerable and at times surprising advantages of statistical models over the considered judgments of experienced clinicians and experts. Today, these models are emerging all over the landscape. Whether the field is wine, baseball, medicine, or consumer relations, they are vying against traditional experts for control over how we make decisions. For the legal system, the take-home of Ayres's book and the examples he describes is …

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 …

Law, Statistics, And The Reference Class Problem, Edward K. Cheng

Vanderbilt Law School Faculty Publications

Statistical data are powerful, if not crucial, pieces of evidence in the courtroom. Whether one is trying to demonstrate the rarity of a DNA profile, estimate the value of damaged property, or determine the likelihood that a criminal defendant will recidivate, statistics often have an important role to play. Statistics, however, raise a number of serious challenges for the legal system, including concerns that they are difficult to understand, are given too much deference from juries, or are easily manipulated by the parties' experts. In this preview piece, I address one of these challenges, known as the "reference class problem," …

Experts, Mental States, And Acts, Christopher Slobogin

Vanderbilt Law School Faculty Publications

This article, written for a symposium on "Guilt v. Guiltiness: Are the Right Rules for Trying Factual Innocence Inevitably the Wrong Rules for Trying Culpability?," argues that the definition of expertise in the criminal justice system, derived in the federal courts and in most states from Daubert v. Merrell Dow Pharmaceuticals Co., should vary depending on whether the issue involved is past mental state or past conduct. While expert psychological testimony about past acts ought to be based on scientifically verifiable assertions, expert psychological testimony about subjective mental states relevant to criminal responsibility need not meet the same threshold. This …

The Perils Of Evidentiary Manipulation, Edward K. Cheng

Vanderbilt Law School Faculty Publications

The use of evidentiary rules to achieve substantive goals strikes me as a Faustian bargain, and, given Bierschbach and Stein's acknowledgedly tentative position, I hope to dissuade them of the virtues of the practice. My goal therefore is to explore briefly the potential dark side of specialized evidentiary rules. The concerns of injecting substantive goals into evidence law extend far beyond the narrow legitimacy concerns Bierschbach and Stein raise. It is not simply the question of whether we aspire to a pluralistic or majority-take-all democratic society. Rather, evidentiary manipulation threatens the legitimacy of criminal and evidence law... Bierschbach and Stein's …

Independent Judicial Research In The "Daubert" Age, Edward K. Cheng

Vanderbilt Law School Faculty Publications

The Supreme Court's Daubert trilogy places judges in the unenviable position of assessing the reliability of often unfamiliar and complex scientific expert testimony. Over the past decade, scholars have therefore explored various ways of helping judges with their new gatekeeping responsibilities. Unfortunately, the two dominant approaches, which focus on doctrinal tests and external assistance mechanisms, have been largely ineffective. This Article advocates for a neglected but important method for improving scientific decision making-independent judicial research. It argues that judges facing unfamiliar and complex scientific admissibility decisions can and should engage in independent library research to better educate themselves about the …

Should Judges Do Independent Research On Scientific Issues?, Edward K. Cheng

Vanderbilt Law School Faculty Publications

Judges are deeply divided about the issue of independent research, which goes to the heart of their roles and responsibilities in the legal system. To many judges, doing independent research when confronted with new and unfamiliar material seems the most responsible and natural thing to do. To others, it represents the worst kind of overreaching and a threat to long-cherished adversarial values. But whether one supports the practice or not, one thing is clear. The issue of independent research deserves far greater attention than it has so far from jurists, academics, and practitioners alike.

Dangerousness And Expertise Redux, Christopher Slobogin

Vanderbilt Law School Faculty Publications

Civil commitment, confinement under sexual predator laws, and many capital and noncapital sentences depend upon proof of a propensity toward violence. This Article discusses the current state of prediction science, in particular the advantages and disadvantages of clinical and actuarial prediction, and then analyzes how the rules of evidence should be interpreted in deciding whether opinions about propensity should be admissible. It concludes that dangerousness predictions that are not based on empirically derived probability estimates should be excluded from the courtroom unless the defense decides otherwise. This conclusion is not bottomed on the usual concern courts and commentators raise about …

Same Old, Same Old: Scientific Evidence Past And Present, Edward K. Cheng

Vanderbilt Law School Faculty Publications

For over twenty years, and particularly since the Supreme Court's Daubert' decision in 1993, much ink has been spilled debating the problem of scientific evidence in the courts. Are jurors or, in the alternative, judges qualified to assess scientific reliability? Do courts really need to be concerned about "junk science"? What mechanisms can promote better decision making in scientific cases? Even a cursory scan of the literature shows the recent explosion of interest in these issues, precipitating new treatises, hundreds of articles, and countless conferences for judges, practitioners, and academics.

Reenvisioning Law Through The Dna Lens, Edward K. Cheng

Vanderbilt Law School Faculty Publications

In recent times, no development has transformed the practice of criminal justice as much as DNA evidence. In little over fifteen years, DNA profiling has produced nothing short of a paradigm shift.1 For police and prosecutors, DNA has become a potent weapon for identifying and convicting criminals. Trace biological material left at a crime scene now provides critical evidence for generating leads through "cold searches" of DNA databases and for convicting defendants at trial. At the same time, for defense attorneys, DNA has become an invaluable tool for seeking exonerations, because just as DNA can link defendants to crimes, it …