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Are expert witnesses really necessary?


You bet they are. Jurors love expert testimony and expert witnesses. As a Jacksonville criminal defense lawyer, I always try and put an expert witness on the stand. Why? Because the prosecutor will almost always try and put expert testimony before a jury; it often fills the cracks in an otherwise weak or questionable case. Expert testimony helps to secure convictions. The only problem is, sometimes the science behind the expert testimony turns out to be unreliable or false.

Take the case of arson. Dozens of arson prosecutions have come under scrutiny lately because of entrenched but now discredited beliefs about how arson can be detected. The Arson Research Project has highlighted at least 31 wrongful convictions based on now debunked fire investigations, including, most notably (and chillingly) the conviction and execution of Cameron Todd Willingham in Texas, an innocent man.

Or take the case of Han Tak Lee, a South Korean immigrant convicted of first degree murder and sentenced to life without parole when he supposedly set fire to a Pennsylvania cabin in which his daughter was killed. The arson science and expert testimony turned out to be flawed and wrong. Now, after having served nearly 25 years in prison, a federal magistrate recommended that Lee should either be given a new trial or released from prison outright. "There was just no science behind the old assumptions about arson", said Paul Cates of The Innocence Project. "A lot of this was just guesswork and voodoo". Lee, now 79 years old, has consistently maintained his innocence.

At the time, arson investigators were taught that unusually hot and intense fires indicated the use of an accelerant and that arson could be confirmed by the presence of deep charring or shiny blistering of wood as well as "crazy glass', tiny fractures in windows. Fire research conducted in the 1980's debunked these and other notions about arson. By 1992, the National Fire Protection Association had published new standards to guide fire investigations. But arson investigators, many of whom testify as "experts" at criminal trials for the government, were slow to accept the new science. 25 years later, U.S. Magistrate Judge Martin Carlson said scientific progress had invalidated the conviction of Mr. Lee. "Over the past two decades, there has been a revolution in fire science", he wrote. "It is a revolution that has toppled old orthodoxies and cast into doubt longstanding assumptions regarding fire science analysis".

How could these so-called experts continue to testify the way they always had ? Because old way die hard and old experts, set in their ways, don't want to admit they were wrong. There are experts in just about every field and on just about every subject. Some are qualified in known subjects like ballistics and fingerprints. Some are highly questionable, like psychiatrists that have been permitted to testify in some rape trials about the field of 'repressed memories' by victims. Is there any way to prevent the prosecutor from calling some of these 'experts' to the witness stand?

Yes, there is. Request a Daubert hearing in front of the trial judge, which is a hearing to evaluate the admissibility of an expert's testimony. It is a hearing held out of the jury's presence and before the trial even begins. The trial judge will make a determination of whether an expert's scientific testimony is based on reasoning or methodology that is scientifically valid and can properly be applied to the facts at issue. The judge must determine whether (1) the theory can be and has been tested, (2) whether it has been subjected to peer review and publication, (3) it's known or potential error rate, (4) the existence and maintenance of standards controlling its operation and (5) whether it has attracted widespread acceptance within a relevant scientific community.

Lesson Learned:

Even with a Daubert hearing, the decision to allow certain types of expert testimony is still somewhat subjective and up to trial judge, who may be right or may be wrong. It's best, if you can afford it, to be able to counter the government expert with your own expert, so that the jury will have more than just the government's expert point of view to consider.

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