Evidence Commons^™

Amicus Brief: Kumho Tire V. Carmichael, Neil Vidmar, Richard Lempert, Shari Diamond, Valerie Hans, Stephan Landsman, Robert Maccoun, Joseph Sanders, Harmon Hosch, Saul Kassin, Marc Galanter, Theodore Eisenberg, Stephen Daniels, Edith Greene, Joanne Martin, Steven Penrod, James Richardson, Larry Heuer, Irwin Horowitz

Robert MacCoun

This brief addresses the issue of jury performance and jury responses to expert testimony. It reviews and summaries a substantial body of research evidence about jury behavior that has been produced over the past quarter century. The great weight of that evidence challenges the view that jurors abdicate their responsibilities as fact finders when faced with expert evidence or that they are pro-plaintiff, anti-defendant, and anti-business.

The Petitioners and amici on behalf of petitioners make a number of overlapping, but empirically unsupported, assertions about jury behavior in response to expert testimony, namely that juries are frequently incapable of critically evaluation …

Economic Authority And The Limits Of Expertise In Antitrust Cases, John E. Lopatka, William H. Page

William H. Page

In antitrust litigation, the factual complexity and economic nature of the issues involved require the presentation of economic expert testimony in all but a few cases. This dependence on economics has increased in recent years because of the courts' narrowing of per se rules of illegality and the courts' expansion of certain areas of factual inquiry. At the same time, however, courts have limited the scope of allowable expert testimony through the methodological strictures of Daubert and its progeny and through heightened sufficiency requirements. In this Article, Professors Page and Lopatka make four important points about these judicially imposed constraints …

Jurors' Evaluations Of Expert Testimony: Judging The Messenger And The Message, Sanja Kutnjak Ivkovic, Valerie P. Hans

Valerie P. Hans

Jurors are laypersons with no specific expert knowledge, yet they are routinely placed in situations in which they need to critically evaluate complex expert testimony. This paper examines jurors' reactions to experts who testify in civil trials and the factors jurors identify as important to expert credibility. Based on in-depth qualitative analysis of interviews with 55 jurors in 7 civil trials, we develop a comprehensive model of the key factors jurors incorporate into the process of evaluating expert witnesses and their testimony. Contrary to the frequent criticism that jurors primarily evaluate expert evidence in terms of its subjective characteristics, the …

Science On Trial, Valerie P. Hans

Valerie P. Hans

The increasing complexity of both criminal and civil jury trials raises a host of issues for lawyers and judges. For the litigator, the first question is whether a jury can be trusted with a case that turns on highly technical evidence. For the trial judge, there are decisions about the admissibility of expert testimony, whether it is based on sound science, and whether a jury is likely to be misled by scientific claims. Should the judge permit jury innovations such as note taking, question asking, and juror discussions of evidence during the trial, hoping to increase jury comprehension of the …

Can Jury Trial Innovations Improve Juror Understanding Of Dna Evidence?, B. Michael Dann, Valerie P. Hans, David H. Kaye

Valerie P. Hans

A single spot of blood on a pink windowsill will tell investigators who broke a windowpane, turned a lock, and kidnapped 2-year-old Molly Evans from her bedroom in the middle of the night. An expert witness will testify that the DNA profile of the blood evidence recovered from the windowsill was entered into CODIS, an electronic database of DNA profiles. That process yielded a “hit,” identifying the defendant as the most likely source of the blood inside Molly’s room. But will jurors be able to understand the expert’s intricate analysis and use it to reach a verdict? And what—if any—steps …

Testing Jury Reforms, Valerie P. Hans, B. Michael Dann, David H. Kaye, Erin J. Farley, Stephanie Albertson

Valerie P. Hans

DNA evidence has become a key law enforcement tool and is increasingly presented in criminal trials in Delaware and elsewhere. The integrity of the criminal trial process turns upon the jury's ability to understand DNA evidence and to evaluate properly the testimony of experts. How well do they do? Can we assist them in the process?

Statistics In The Jury Box: How Jurors Respond To Mitochondrial Dna Match Probabilities, David H. Kaye, Valerie P. Hans, B. Michael Dann, Erin J. Farley, Stephanie Albertson

Valerie P. Hans

This article describes parts of an unusually realistic experiment on the comprehension of expert testimony on mitochondrial DNA (mtDNA) sequencing in a criminal trial for robbery. Specifically, we examine how jurors who responded to summonses for jury duty evaluated portions of videotaped testimony involving probabilities and statistics. Although some jurors showed susceptibility to classic fallacies in interpreting conditional probabilities, the jurors as a whole were not overwhelmed by a 99.98% exclusion probability that the prosecution presented. Cognitive errors favoring the defense were more prevalent than ones favoring the prosecution. These findings lend scant support to the legal argument that mtDNA …

Judges, Juries, And Scientific Evidence, Valerie P. Hans

Valerie P. Hans

The rise in scientific evidence offered in American jury trials, along with court rulings thrusting judges into the business of assessing the soundness of scientific evidence, have produced challenges for judge and jury alike. Many judges have taken up the duty of becoming “amateur scientists.” But what about juries? Surely they too could benefit from assistance as they attempt to master and apply complex testimony about scientific matters during the course of a trial. Concerns about the jury’s ability to understand, critically evaluate, and employ scientific evidence in deciding complex trials have led to many suggestions for reform. This article …

Cross-Racial Identification Errors In Criminal Cases, Sheri Johnson

Sheri Lynn Johnson

No abstract provided.

The New Rules For Admissibility Of Expert Testimony: Part Ii, Robert Sanger

Robert M. Sanger

As described in the last Criminal Justice column for the Santa Barbara Lawyer magazine, the California Supreme Court’s opinion in Sargon Enterprises v. University of Southern California, 55 Cal. 4th 747, 149 Cal. Rptr. 3d 614 (2012) made it clear that California is now, (and perhaps unsuspectingly has been for some time), a Daubert jurisdiction. This requires the trial court be the “gatekeeper” and make a determination as to the admissibility of scientific or expert testimony and to determine the limits of any testimony, if it is introduced. The Court held that there are essentially three criteria: The first criterion …

Jailhouse Informants, Robert M. Bloom

Robert Bloom

No abstract provided.

The New Rules For Admissibility Of Expert Testimony: Part I, Robert Sanger

Robert M. Sanger

In a previous series of articles for this magazine, I took the position that California really was a Daubert jurisdiction in the sense that Kelly and Frye and thenexisting case law required that the court be the “gatekeeper” and make a determination as to: 1) whether a science (or area of expertise) was a science (or area of expertise); 2) whether the witness was a scientist (or expert); 3) whether the data was reliable; and then, and only then, 4) what a true scientist (or expert) could say based on the science and based on the reliable data. In the …

Jailhouse Informants, Robert M. Bloom

Robert M. Bloom

No abstract provided.

Behavioral Science Evidence In The Age Of Daubert: Reflections Of A Skeptic, Mark S. Brodin

Mark S. Brodin

The piece briefly traces the history of the use of social science in the courtroom, and proceeds to critically measure this form of proof (particularly “syndrome” evidence) against both the reliability standards imposed by Daubert v. Merrell Dow Pharmaceuticals, Inc. and the traditional requirements for admission of expert testimony. Drawing upon empirical research concerning juries and decision-making as well as transcripts of the use of behavioral evidence at trial, I conclude that much of this testimony should be rejected. Rather than providing meaningful assistance to the jury, social science experts can distort the accuracy of the fact-finding process and imperil …

3. The Relevance Ratio: Evaluating The Probative Value Of Expert Testimony In Child Sexual Abuse Cases., Thomas D. Lyon, Jonathan J. Koehler

Thomas D. Lyon

Helping Jurors To Make Sense Of Expert Testimony, David Aaronson

David Aaronson