Evidence Commons^™

Science On Trial, Valerie P. Hans

Cornell Law Faculty Publications

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 …

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

Cornell Law Faculty Publications

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

Cornell Law Faculty Publications

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 …

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

Cornell Law Faculty Publications

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

Cornell Law Faculty Publications

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?

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

Cornell Law Faculty Publications

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 …