Cross Examining the Expert Witness: Messing with Hypotheticals

February 11, 2013

Monday, February 11, 2013

I write today about effectively cross examining expert witnesses, which was one of my specialties.

I could write a book about the subject, and maybe someday I will, but today I am going to focus on unraveling the expert’s hypothetical question.

Briefly, Rule 702 of the rules of evidence defines an expert witness as someone who is qualified by education, training or experience to express an opinion regarding a disputed matter in a legal proceeding.

When a jury needs the assistance of an expert witness to decide a disputed matter, either side may present the testimony of a duly qualified expert witness who may express an opinion regarding the disputed matter, including the answer to the ultimate question in the lawsuit.

The party that calls the expert begins by qualifying her as an expert. This normally involves having her tell the jury about her education, training or experience and publications in professional peer reviewed journals. Most experts have a curriculum vitae or CV, that lists their educational credentials and an up-to-date list of their publications. The CV is admitted into evidence.

The expert then tells the jury what evidence she has examined in the case.

Next comes a hypothetical question in which the expert is asked to assume a set of specific facts and asked if she can form an opinion to a reasonable medical or scientific certainty about the significance of those facts.

The witness will answer, “Yes.”

Next question: “What is your opinion?”

Next comes the rat-a-tat-tat of a nail gun.

One of the most effective ways to cross examine an expert is to attack the validity of the assumptions in the hypothetical question.

Undermine one and the expert’s opinion usually falls apart.

Since assumptions typically consist of assuming that disputed facts are undisputed, in a manner that benefits the party that called the expert, the opposing party cross examining the expert simply asks the expert to assume the contrary view.

Another way to challenge an expert opinion is to introduce an additional assumption into the hypothetical that undermines the conclusion.

Let us take, for example, the issue regarding whether Trayvon or the defendant was on top when the defendant fired the fatal shot.

The undisputed facts are the trajectory of the shot, which was direct from front to back, the intermediate range from which the shot was fired, the nonalignment of the two aligned holes in the sweatshirts with the entry wound and the muzzle of the gun was in contact with the outer sweatshirt when the fatal shot was fired.

The disputed fact is whether Trayvon or the defendant was in the superior position straddling the other.

The defense probably could find an expert who, given those undisputed facts, could testify to a reasonable scientific certainty that the defendant was on the bottom when he fired the fatal shot.

The problem with the hypothetical, however, is that it does not account for the presence of the gun in the defendant’s hand.

According to the defendant’s statement, he pulled the gun out of the holster that he carried inside the waistband of his jeans behind his right hip.

The expert’s opinion falls apart when you add this undisputed fact to the hypothetical because the defendant could not draw the gun and get it into the necessary position to fire the fatal shot.

Note BTW, that one also could conclude to a reasonable scientific certainty from the original set of undisputed facts that the defendant was in the superior position straddling Trayvon.

This is how you shoot down credentialed experts in just a few words.


Was Trayvon Martin a Peaceful and Non-violent Person?

January 13, 2013

I write today regarding a game within the game. I am specifically referring to trial by ambush despite discovery rules that require the prosecution to basically turn over everything it has to the defense long before trial.

My inspiration to write about this subject comes from a series of questions asked by Diaryofasuccessfulloser, who wanted to know where to find evidence that Trayvon was a peaceful and non-violent person in the discovery that has been released.

You can look but you will not find much.

The discovery rules require the prosecution to identify the witnesses it intends to call and to provide copies of their statements to the defense and to the public.

Those statements do not necessarily include all of the information obtained from those witnesses. Defense counsel have a duty to investigate their cases and that includes tasking an investigator to interview the witnesses or to be present and take notes when the lawyer interviews them. Florida permits the use of depositions under oath in criminal cases.

Interviews and depositions provide an opportunity to obtain information not included in the statements and reports.

The best source of information about Trayvon’s non-violent and peaceful nature is his family and friends like Dee Dee. She described him that way to Benjamin Crump and to Bernie de la Rionda. So did the librarian where he used to study after school. His parents have described him that way publicly.

Note that the defense, which has been trying its case in the court of public opinion, has not produced any evidence at all to support its claim that he was an aggressive martial arts enthusiast who picked fights and bullied others. Obviously his school records contained no information to support that claim or the defense would have shouted it from the tree house.

According to the complaint filed by the security/investigation firm, the investigators did not find out anything useful to the defense about Trayvon. We do not know what they were tasked to do, but given the importance of such evidence to support the defendant’s claim, I suspect they looked for such evidence, but did not find it.

The absence of evidence to support the defense claim might reasonably be considered evidence that he was not an aggressive martial arts enthusiast who picked fights and bullied others.

That absence of evidence is consistent with what we have heard from his family and Dee Dee.

There are other witnesses too. I vaguely recall his former football coach describing him that way, for example.

In other words, you have to read between the lines sometimes because the prosecution is not required to document all of its evidence.

Remember that most witness statements and reports will never be admitted into evidence because most of them are hearsay. The evidence in court will consist of the exhibits admitted into evidence and the testimony of the witnesses under oath

Witness statements and reports rarely contain the whole story. They are like movie trailers and serve as a starting point to find out what the witness knows. Only a fool would assume that they contain all of the relevant information that a witness knows.

The prosecution has no obligation to reduce all of that information to writing and share it with the defense. The prosecution is only obligated to disclose exculpatory evidence to the defense and this evidence is not exculpatory. Evidence that Trayvon was peaceful and non-violent hurts the defense. Therefore, the prosecution has no duty to reveal it to the defense, unless it is in a statement.

I suspect the prosecution has a lot of evidence that has not been recorded or written down anywhere in a report.

Part of the game is to conceal as well as reveal only that which you are required to reveal.

The only way the defense can discover the information not included in the reports is to use an investigator to find it or acquire it during a deposition.

Unfortunately, the defense does not appear to have any investigators or experts to assist the lawyers.

This is one reason why I have been so critical of the defense effort. With the exception of the one report we know about, which they did not pay for, the defense appears to have sacrificed the use of investigators in favor of maintaining and paying for the defendant’s comfort and unnecessary security. In a case where the forensics likely will determine the outcome, the defense also appears to have sacrificed the use of experts for the same two reasons.

With O’Mara potentially indebted to the security/investigation firm for $27,000 and not having been paid a cent for the work he has performed, I can only shake my head in amazement that the priorities in this case are so upside down.

This is what can happen when a lawyer lets a selfish and clueless client run the show.


Forensic Fraud (Part 2)

January 13, 2012

As I said yesterday in Part 1,

One of the biggest problems we’ve seen in crime labs is people testifying as experts regarding matters beyond their expertise.

This happened in Crane-Station’s case when a lab tech with a bachelor’s degree from Transylvania University in Lexington, KY, who routinely analyzes human blood samples for controlled substances in the Central Lab of the Kentucky State Crime Laboratory using gas chromatography and mass spectrometry (GCMC), testified as an expert toxicologist regarding the probable effects of Clonazepam on her. He was permitted to do this without objection from her lawyer, even though,

(1) he had not detected Clonazepam, or any other drugs in her blood when he analyzed her sample;

(2) he had no formal training in drug toxicology;

(3) he never had published a peer reviewed article in a professional journal on any subject;

(4) he did not know what constituted a toxic level of Clonazepam in human blood, as opposed to a safe level;

(5) the prosecutor told him that she had admitted taking her prescribed medication when she was arrested, which included Clonazepam, but he had no information regarding what dosage she had taken and when she had taken it.

Nevertheless, he was permitted to express his opinion as an ‘expert’ that she was probably under the influence of and impaired by Clonazepam when the deputy stopped her.

This was a travesty of speculative nonsense and never should have happened.

Now, how is it possible that she could have been under the influence of and impaired by Clonazepam, if he did not detect it in her blood sample?

Well, he testified that it is difficult to detect using gas chromatography and he might have been able to detect it using liquid chromatography, but the Kentucky State Crime Lab cannot afford the equipment to perform that analysis.

Could some other lab have performed the analysis?

Well, as a matter of fact, NMS Labs in Philadelphia can do it and the Kentucky State Crime Laboratory has a contract with NMS to do the test.

Did that happen in Crane’s case?

According to the Director of the Kentucky State Crime Laboratory, the lab sent her blood sample to NMS.

But Ryan Johnson claims that he did not send her blood sample to another lab and the prosecution denies that another lab tested her sample, or that there is an exculpatory lab result from NMS.

However, there is a 2-month gap between the date that Ryan Johnson completed his analysis and the date that it was approved by his supervisor.

Sure looks like he completed his analysis and sent her sample to NMS. They tested it and sent it back reporting an exculpatory result confirming his analysis without generating a written report, so his supervisor reviewed and signed off on his exculpatory result. Then the prosecution turned over his report without mentioning the NMS report.

NMS has referred all inquiries to the prosecutor and, as I said, the prosecutor claims there is no NMS Report or analysis.

This is the kind of bullshit that we are dealing with.


Opinion Evidence, Expert Witnesses, And The Plight Of The Injured Plaintiff

January 9, 2012

Junk science and the charlatans for sale who rely on it while masquerading as objective experts above the fray of litigation constitute a serious and continuing problem to the fair administration of justice in our legal system.

The Federal Rules of Evidence (FRE) distinguish between ordinary witnesses and expert witnesses. With a few exceptions, such as whether a person appeared to be intoxicated or how fast someone was driving, ordinary witnesses are supposed to restrict their testimony to facts they perceive through their five senses. Experts are permitted to express opinions that are typically expressed to a “reasonable scientific (or medical) certainty.” A major part of the problem for indigent and poor plaintiffs is lack of sufficient funds to hire sufficiently qualified experts. Plaintiffs personal injury lawyers usually advance the costs of such witnesses and reimburse themselves out of a favorable money judgment. In practice, this means that they will not agree to take a case unless they are virtually certain they will win. It also means that the lawyer or firm that takes the case must have a big war chest and there are not very many who do. Meanwhile, corporations and insurance companies have virtually unlimited funds available to retain multiple experts and they routinely subject plaintiffs to delays and hurdles to leap until money runs out and they settle the case for less than it is worth or they drop out.

Fortunately, in criminal cases, an indigent defendant has a Sixth Amendment right to have the court appoint and compensate an expert when an expert’s assistance is “reasonably necessary” to present a defense. Ake v. Oklahoma, 470 U.S. 68 (1985).

There are any number of urban legends about undeserving plaintiffs who won multiple million dollar judgments against ‘poor’ corporations and insurance companies, but I doubt that any of the stories are true. Even if some of them are true, they pale when considering the following studies.

When considering whether there should be limits on tort liability for damages due to personal injury, keep in mind that, according to HealthGrades’ fifth annual Patient Safety in American Hospitals Study, patient safety incidents cost the federal Medicare program $8.8 billion and resulted in 238,337 potentially preventable deaths during 2004 through 2006.

This study followed HealthGrades’ studies in 2000-2002 that reported 195,000 preventable deaths per year in U.S. hospitals.

Here are the applicable rules regarding ordinary and expert witness testimony.

As you read the rules and my discussion of Daubert v. Merrell Dow Pharmaceuticals that follows, keep in mind that one of the many evidence-based debates that we should be having as an educated democratic society, but tragically are not having, is what should we do to reform these rules and other practices to assure fair and equitable results to economically disadvantaged people who suffer personal injury.

Rule 701 provides:

If the witness is not testifying as an expert, the witness’ testimony in the form of opinions or inferences is limited to those opinions or inferences which are

(a) rationally based on the perception of the witness,

(b) helpful to a clear understanding of the witness’ testimony or the determination of a fact in issue, and

(c) not based on scientific, technical, other specialized knowledge within the scope of Rule 702.

Rule 702 provides:

If scientific, technical, or other specialized knowledge will assist the trier of fact to understand the evidence or to determine a fact in issue, a witness qualified as an expert by knowledge, skill, experience, training, or education, may testify thereto in the form of an opinion, or otherwise, if

(1) the testimony is based upon sufficient facts or data,

(2) the testimony is the product of reliable principles and methods, and

(3) the witness has applied the principles and methods reliably to the facts of the case.

In Daubert v. Merrell Dow Pharmaceuticals, Inc., 509 U.S. 579 (1993), the United States Supreme Court reversed the Ninth Circuit Court of Appeals decision affirming the trial court’s dismissal of the plaintiffs’ lawsuit against Merrell Dow Pharmaceuticals for birth defects allegedly caused by Bendectin, a drug manufactured by Merrell Dow to prevent pregnant women from suffering morning sickness. The plaintiffs had relied on in vitro and in vivo animal studies, pharmacological studies, and reanalysis of other published studies to show that Bendectin could have caused the birth defects. Nevertheless, trial court had dismissed their lawsuit based on the Frye Rule, which prohibits the use of evidence that has been obtained from using a scientific methodology or process that has not been generally accepted in the scientific community.

The United States Supreme Court rejected the Frye Rule in Daubert as unnecessarily restrictive of new discoveries in science because it amounted to little more than counting heads in the scientific community to determine if a principle or methodology was generally accepted rather than evaluating the merits of the new principle or methodology. Therefore, even though the scientific community had not yet generally accepted that Bendectin caused birth defects, the Court concluded that the studies relied on by the plaintiffs were sufficient such that they should have been been permitted to present them to a jury to consider.

In Daubert the Court basically appointed trial judges to function as gatekeepers in determining whether to admit evidence based on novel scientific principles or methodologies. The Court set forth a non-exclusive checklist for trial judges to apply in assessing the reliability of scientific evidence. The specific factors the Court mentioned are:

(1) whether the expert’s technique or theory can be or has been tested according to some objective process,

(2) whether the technique or theory has been subjected to peer review and publication,

(3) whether there was a known or potential rate of error for the technique or theory and, if so, whether it was applied,

(4) whether applicable laboratory standards and controls were used, and

(5) whether the technique or theory used has been generally accepted in the scientific community (which is the Frye Rule downgraded from an outcome-determinative rule to one of several factors that should be considered).


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