Posts Tagged ‘scientific research’

In a newly-published study, researchers find that forensic experts rendering opinions may unconsciously bias their results toward the parties that employ them.  The results have potentially broad application across a wide variety of traditional forensic disciplines.

The journal Psychological Science has posted the study, called “Are Forensic Experts Biased by the Side That Retained Them?”  (I thank The Crime Report, from John Jay College of Criminal Justice, for bringing it to my attention.)  The authors, Daniel C. Murrie, Marcus T. Boccaccini, Lucy A. Guarnera, and Katrina A. Rufino, tested the idea that forensic experts called upon to evaluate evidence in an adversarial legal proceeding might respond differently, depending solely upon which party asked them to perform the evaluation.  Here’s the abstract to the study:

How objective are forensic experts when they are retained by one of the opposing sides in an adversarial legal proceeding? Despite long-standing concerns from within the legal system, little is known about whether experts can provide opinions unbiased by the side that retained them. In this experiment, we paid 108 forensic psychologists and psychiatrists to review the same offender case files, but deceived some to believe that they were consulting for the defense and some to believe that they were consulting for the prosecution. Participants scored each offender on two commonly used, well-researched risk-assessment instruments. Those who believed they were working for the prosecution tended to assign higher risk scores to offenders, whereas those who believed they were working for the defense tended to assign lower risk scores to the same offenders; the effect sizes (d) ranged up to 0.85. The results provide strong evidence of an allegiance effect among some forensic experts in adversarial legal proceedings.

If these results stand the test of time, the implications are potentially great,  As discussed in the National Academy of Sciences’ landmark 2009 report “Strengthening Forensic Sciences in the United States: A Path Forward,” most forensic disciplines (outside of DNA identification and those that use traditional chemical analysis) rely to a significant degree on human interpretation to generate conclusions.  The results of the Murrie et al. work suggest that all of these disciplines may be influenced by a very important piece of context — who pays for their work — regardless of which side of the case that is.  The study would seem to support one of the central recommendations of the National Academy of Sciences report: “removing all public forensic laboratories and facilities from the administrative control of law enforcement agencies or prosecutors’ offices” (p. 24).

In today’s world, we think of DNA matching as the gold standard of identification: a scientifically precise method of matching human tissue or fluids left at a crime scene to a particular individual.  But in an op-ed article last week, High-Tech, High-Risk Forensics, published in the New York Times, Cal Hastings professor of law Osagie Obasogie reminds us that even DNA identification isn’t foolproof.  It’s an excellent point and one worth remembering.  But then he stumbles over the details of DNA identification, labeling it high risk, because many people might have the same DNA profiles.  Risk is always present, but is the risk of getting DNA identifications high because many people might have the same DNA profile?  No.

Professor Obasogie tells us the story of a man arrested for a murder near San Jose, California, when his DNA was found on the victim’s body.  Only after the man was arrested and jailed did his alibi surface: at the time of the murder, he was a patient at a hospital, suffering from severe intoxication, and there were voluminous records to prove it.  He was freed after five months, and prosecutors now think the most likely explanation is that paramedics who transported the man to the hospital were the same ones called to the crime scene later that night.  The DNA was likely transferred to the victim from the paramedics’ clothing or equipment.  Professor Obasogie decries “the certainty with which prosecutors charged Mr. Anderson with murder,” because it  “highlights the very real injustices that can occur when we place too much faith in DNA forensic technologies.” This is hard to argue with; for those who can remember this far back, it recalls lawyer Barry Scheck cross-examining Dennis Fung in the O.J. Simpson murder trial over the sloppy collection of DNA and other evidence.  Scheck and other lawyers argued that the DNA that seemed to implicate Simpson just couldn’t be trusted; “garbage in, garbage out.” Professor Obasogie is not saying that the paramedics did anything wrong or were sloppy in any conventional sense; rather he’s arguing (correctly) that contamination can happen even when we’re not aware of the possibility.  Thus caution is always advisable, even with DNA.

But then Professor Obasogie begins to argue that there are deeper problems with DNA identification than just contamination.

Consider the frequent claim that it is highly unlikely, if not impossible, for two DNA profiles to match by coincidence. A 2005 audit of Arizona’s DNA database showed that, out of some 65,000 profiles, nearly 150 pairs matched at a level typically considered high enough to identify and prosecute suspects. Yet these profiles were clearly from different people.

Professor David H. Kaye of Penn State Dickinson School of Law has pointed out the problem with this argument on his blog Forensic Science, Statistics & the Law.  In a blog post on July 26, Professor Kaye explains why Professor Obasogie is wrong on this point.  In his words:

The 150 or so matches were, in fact, mismatches. That is, they were partial matches that actually excluded every “matching” pair. Only if an analyst improperly ignored the nonmatching parts of the profiles or if these did not appear in a crime-scene sample could they be reported to match.

There is much more to Professor Kaye’s thorough and lucid explanation.  If you are interested in a real understanding of how DNA actually works, I strongly recommend Professor Kaye’s post.

On Thursday April 4, and Friday April 5, I’ll be in Cincinnati for two discussions of Failed Evidence: Why Law Enforcement Resists Science (2012).  Both are free and open to the public.

On April 4, I’ll be discussing the book at 7:00 p.m. at the Clifton Cultural Arts Center, 3711 Clifton Avenue, Cincinnati OH 43220.  The event is sponsored by the ACLU of Ohio.

On April 5, I’ll present at talk at the University of Cincinnati College of Law at noon.  The address is  2540 Clifton Ave, Cincinnati, OH 45221.  The event is in Room 114.  The event is sponsored by the Lois and Richard Rosenthal Institute for Justice/Ohio Innocence Project.  The event has been approved for CLE credit for attorneys.

In another sign that resistance to better, science-based practices will eventually have to yield, a news report indicates that a member of the South Carolina has  introduced a bill that would require police to record interrogations of suspects.

The bill, proposed by Rep. Todd Rutherford of Columbia, “would require judges to instruct jurors that they could ‘draw an adverse inference’ if a law enforcement officer failed to record the questioning of a suspect unless there was an equipment failure.”  That required instruction would effectively require that the police record interrogations, because jurors would hear from the court that the interrogation might be suspicious.

Even if the bill does not pass, the significance of the proposal is hard to miss.  An increasing number of states and jurisdictions require recording of interrogations under various circumstances (see the Innocence Project’s map here), and the research shows that the recording requirement does not harm the investigation process.  In fact, recording turns out to be a great help to the police overall.  The research of Thomas Sullivan on the practical effects of recording has been particularly insightful and helpful on this issue, and academics such as Richard Leo, Saul Kassin, and Richard Ofshe have made tremendous contributions in the area of false confessions and why recording can help.

More to the point, South Carolina would not be viewed by anyone as a jurisdiction that has been particularly favorable to defendants on criminal justice issues.  The fact that the legislature in South Carolina now has a proposal to consider on recording interrogations means that, little by little, we are nearing a tipping point, which will bring us closer to what the scientific research shows us.

 

The current issue of Science magazine contains a review of Failed Evidence: Why Law Enforcement Resists Science (NYU Press, 2012).  Here is a brief excerpt from the review:

Although science has long been recognized as our most reliable pathway to truth, people are sometimes reluctant to accept scientific evidence, particularly when it challenges established practices or cherished beliefs. In Failed Evidence: Why Law Enforcement Resists Science, David A. Harris accuses police and prosecutors of unwarranted skepticism toward science and tries to explain their perspective. His provocative book will interest those concerned broadly with rejection of science as well as those interested in the U.S. criminal justice system.

Science is published by the American Association for the Advancement of Science.

A decision by Oregon’s Supreme Court on eyewitness identification procedures has re-set the way that juries and courts in that state will think about eyewitness identification.

According to the New York Times editorial on the case, the ruling shifts the burden of proof to prosecutors to prove that eyewitness identifications are reliable before they can be admitted in court.  Before last week’s decision, the rule had been that identifications were generally admitted; it was up to the defense in individual cases to prove that an identification was not reliable.

But at least as important as the new rule itself was the reason that the Oregon court abandoned its old precedent:  the court had concluded that the old rule was based on assumptions about eyewitness testimony no longer supported by the science.  Thus the new case represents a textbook case of a court forcing law enforcement away from the failed evidence of discredited methods, and toward methods that accord with what science teaches us now.

Under the old rule, Oregon judges looked at five factors when evaluating an eyewitness identification: opportunity to view the alleged perpetrator, attention to identifying features, timing and completeness of description given after the event, certainty of description and identification by witness, and lapse of time between original observation and the subsequent identification.  Looking at these factors from the vantage point of the present day, the Oregon court found them “incomplete and, at times, inconsistent with modern scientific findings.”  Given the science on eyewitness identification that is by now well established, the court prescribed a new approach, including the change in the burden of proof.

That’s what the Oregon Supreme Court did, but here is why they did it:

…[W]e believe that it is imperative that law enforcement, the bench, and the bar be informed of the existence of current scientific research and literature regarding the reliability of eyewitness identification because, as an evidentiary matter, the reliability of eyewitness identification is central to a criminal justice system dedicated to the dual principles of accountability and fairness.

It’s hard to imagine a better summing up of the ideas behind Failed Evidence, and why the fight to overcome law enforcement’s general resistance to science is so important.

This week, Jurist, a national and international legal reporting website, is featuring my commentary on Failed Evidence.   Here’s a quick sample:

[The] image of a deep alliance between police work and modern science is misleading at best. With the exception of DNA work and certain kinds of classic chemical analysis, law enforcement generally does not embrace existing scientific work. In fact, police and prosecutors in the US resist science. The scientific work I am referring to involves the testing of the more traditional techniques of law enforcement investigation and prosecution: not the high-tech sheen of the DNA lab, but scientific testing of eyewitness identification, the interrogation of suspects and the more traditional forensic methods such as fingerprint identification. This is the daily bread and butter of law enforcement, and scientists have found it wanting. The science on these basic police investigation methods has existed for years — some of it for decades. It is rigorous, and has undergone peer review, publication and replication. It tells us what the problems with traditional police work are, and also gives us some straightforward ways of solving these problems. Yet, most — not all, to be sure, but most — of American law enforcement continues to resist this science and refuses to change its basic tactics to reflect the best of what science has to offer.

Jurist mixes straight reporting and commentary from the U.S. and around the world; it’s a great source for anyone interested in issues of justice and how it plays out in domestic and international situations around the world.  (Full disclosure: Jurist is supported by my own institution, the University of Pittsburgh School of Law, and has been guided and run since the beginning by my esteemed colleague, Professor Bernard Hibbitts.)  Check it out.

In connection with my talk on Failed Evidence at U. Minnesota Law School Thursday, Nov. 8, take a look at my Commentary piece in today’s Minneapolis Star Tribune, “In Some Areas, Law Enforcement Still Resists Science.”  Here’s a sample:

Everywhere you look, law enforcement and science seem to have formed a partnership. Look at the headlines on any given day, and there’s something like “DNA convicts killer in 1992 cold case.” Turn on the television, and there are the police in “CSI” and its innumerable clones solving cases with high-tech gadgets and test tubes and computers. The message is clear: The bad guys don’t stand a chance against the police officer and the scientists working together.

There is some truth to this: DNA has become an identification tool of unequaled power. But look beyond DNA, and you’ll see something different: When the science concerns eyewitness identification, suspect interrogations, or more traditional, non-DNA forensic testing, law enforcement doesn’t embrace science. Most police agencies and prosecutor’s offices in the United States actively resist the scientific findings on these common types of police investigation.

For those who would like a chance to read a bit of Failed Evidence: Why Law Enforcement Resists Science, the Utne Reader has posted an online version of the first chapter of the book.  You can get to it by clicking here.

Failed Evidence: Why Law Enforcement Resists Science will be the subject of two public forums this week, one in Washington, D.C., and the other in Baltimore.  Both events are free and open to the public.

On Wednesday, October 3, I’ll discuss the book at noon at American University’s Washington College of Law, 4801 Massachusetts Avenue N.W. (6th floor).  My talk will be followed by a panel discussion featuring former Assistant U.S. Attorney Dan Zachem and Professor Paul Butler of Georgetown University.  Full details are here.

On Thursday, October 4, I’ll lead a discussion of the book at 5:30 p.m. at the University of Baltimore School of Law, 1401 Charles Street.  The panel to follow will include Gregg Bernstein, the elected State’s Attorney for Baltimore.  Full details are here.