7 Things to Look for in a Chemistry Expert Witness

Important Criteria in Selecting Your Next Expert


Choosing an expert witness in a case involving issues of chemical testing and analyses can be confusing to an attorney who does not have a background in chemistry.  Many of the considerations for choosing a chemistry expert are similar to choosing an expert generally; however, it is particularly important to select an expert who has the right type of training and subject matter expertise within a relevant sub-discipline of chemistry.  This white paper explores these issues and provides recommendations for lawyers who are looking to identify an expert witness in this complicated area of science.

#1:  Relevant Training

An expert’s education and training must be top-notch to withstand scrutiny from the other side and build trust with judges and juries.  In the field of chemical analysis, this means that the expert should have strong academic credentials, preferably a Ph.D. in a relevant subfield of chemistry, and years of experience using the applicable instrumentation.  Oftentimes, the most qualified chemists will spend additional years doing post-doctoral work or working in industry to hone their skill at analytical chemistry.

#2:  Subject Matter Expertise

As one practitioner notes, “[n]o matter how impressive the expert’s qualifications, they must closely match the subject matter of the testimony.”[1] Chemistry has many sub-disciplines, including analytical chemistry, biochemistry, inorganic chemistry, organic chemistry, and materials chemistry, among others.  When a case calls for a chemistry expert, lawyers should first consult experts with a broad-based problem-solving approach to chemical analysis problems.  These experts can then identify the appropriate individual with a background relevant to the proposed testimony.

Case Study

In a products liability case that our Chief Scientist handled during his career, plastic pipes were breaking inside of a tank, causing leakage and damage to the interior of people’s homes.  The attorney on the case found a number of prospective experts – all of whom had Ph.D.’s in their respective fields.  One expert with a mechanical engineering background specialized in the structure of materials.  Another Ph.D. chemist had an analytical chemistry degree and experience in the study of small molecules. The third Ph.D. was an organic chemist with expertise in chemical structure and the synthesis of materials.

The attorney decided to use a polymer chemistry expert who was knowledgeable about the composition of polymers because the case hinged on the role of additives in protecting polymers.  Because polymers are unstable and can degrade quickly without certain additives, the expert needed to know about the effect that the lack of certain additives had on polymers.  In this case, the expert analyzed the polymers for identification and quantitation of polymer additives.

This case illustrates that not all engineers are alike in their background.  Their subspecialties need to be matched carefully with the problem at hand for effective problem solving and success of the expert in presenting his case with scientific credibility.

#3:  Reliable Methods

Rule 702 of the Federal Rules of Evidence allows a witness “qualified as an expert by knowledge, skill, training, experience, or education” to testify if, among other requirements, “the testimony is the product of reliable principles and methods.”  In Daubert v. Merrell Dow Pharmaceuticals, the Supreme Court held that “the requirement that an expert’s testimony pertain to ‘scientific knowledge’ establishes a standard of evidentiary reliability.”[2] If an expert lacks sufficient scientific knowledge in the specific area of chemistry at issue in the trial, a motion to strike his or her testimony under Daubert is more likely to be successful.

In order to analyze chemistry issues in litigation, a chemistry expert must perform experimental work.  Such work is often is conducted in a laboratory.  While some experts have access to labs of their own, many experts outsource such work to other commercial labs.  Integrity of the data is essential in establishing the credibility of the expert’s report.  For example, can the expert testify that an instrument he or she uses is calibrated regularly?  Furthermore the expert must have a valid method for collecting the data.  After data collection, the expert must interpret the chemical data.  The question then is whether the interpretation is based on a scientific method.

Case Study

In one case involving the corrosion of metallic components in an automobile, the issue was who would be liable for the product failure.  Did the problem arise with the vendor who supplied the initial parts, the vendor who provided the polymer coatings, or the automaker who assembled the parts into the final product?  The right expert was able to perform the necessary testing in a lab to which he had full access and where he directly supervised the technicians.  The expert was able to choose the appropriate methods from the directory ASTM (American Society of Testing Materials).  He used the correct, peer-reviewed methods and was able to draw conclusions that were not vulnerable to attack under Daubert.

#4:  Courtroom Presence

“Probably the greatest intangible factor in selecting an expert is how the individual will appear to a jury.”[3] There are many highly qualified chemists who have sterling credentials and academic reputations, with many publications in their field.  However, not all of these individuals can communicate complicated ideas concisely and simply to a jury of laypeople.  Furthermore, as one practitioner notes, “cross-examination at trial is very different from scientific peer review, and issues that may not affect a fellow scientist’s appraisal of the expert’s work may significantly affect a jury’s perception of the expert’s credibility as a witness.”[4]

Case Study

In a jury trial involving product failure, each side offered experts to testify about issues in the case.  One side hired a professor who was renowned his field, had 25 years of experience, conducted pioneering research, and authored two-dozen research papers.  On the other side of the case was a Ph.D. scientist who owned and operated a small laboratory.  The professor presented matter using very complicated and hard to understand scientific terms.  He did not look at the jury, instead looking largely at his notes while he was talking.  Furthermore, he did not speak clearly enough, nor did his voice project.

The relatively younger Ph.D. Chemist explained scientific matters in layperson’s terms and used everyday examples for the jury to understand the cause of the failure. He maintained eye contact, spoke clearly, and was able to successfully convince the jury of his point of view.

#5:  Independence

Juries give greater weight to the testimony of expert witnesses if they perceive the expert’s judgment to be independent of his or her relationship with the party or the attorney in the case.[5] This is why seasoned practitioners almost always recommend using outside, rather than in-house, experts.[6] Juries are often skeptical of paid experts to begin with – the problem is made worse by experts who are employed by the very people for whom they testify.  In the area of analytical chemistry, one option is to select experts who work with independent analytical chemistry laboratories.  These experts generally do not spend most of their time testifying in cases, as the bulk of their work is working for manufacturers and other companies who require failure analysis and deformulation of products.

#6:  Unimpeachable Credibility

An expert’s testimony is only valuable if the jury or judge believes the expert to be an honest person.  If the expert can be attacked for bias, or for a history of lying or professional misconduct, attorneys should reconsider hiring the expert, no matter how qualified he or she may seem.  During the selection process, look for experts who are frank and willing to disclose all information requested.[7]

#7:  Availability

Potential chemical analysis expert witnesses should be available for potentially long and distant trials.  According to one report, “[t]he typical patent case takes two years to resolve.”[8] Often, these cases may also require the expert to travel across the country for depositions, court appearances, and other meetings.  As a result, even the most qualified expert may be useless if he or she cannot commit the time and travel necessary to work on a case.  Attorneys should look for experts who can sign an agreement to make themselves available for the needs of the trial.


Finding an expert witness in a case involving chemical analysis requires a confluence of factors, including: 1) relevant training, 2) subject matter expertise, 3) reliable methods, 4) courtroom presence, 5) independence, 6) unimpeachable credibility, and 7) availability.  Where a case involves issues of chemical analysis and testing, one approach is to contact an analytical testing laboratory. Avomeen has an extensive network of relationships with faculty members at the University of Michigan and Wayne State University, along with a set of Ph.D. expert witnesses on staff.  We can match the needs of the case with a relevant and qualified expert.

If you require litigation support or expert witness services, please contact Avomeen Analytical Services at (800) 930-5450 or visit our website at www.avomeen.com/litigation-support.

[1] Cecil C. Kuhne III, A Litigator’s Guide to Expert Witnesses, American Bar Association GP/Solo, 2006, p. 68.  See also Richard Fried, Jr., Feature: Choosing and Using an Expert Witness, 12 Hawaii B.J. 4, 2008 (“First and foremost, it is essential that the expert’s testimony be firmly within his or her area of expertise.”).

[2] 509 U.S. 579, 590 (1993).

[3] Kuhne, p. 69.

[4] Fried, 12 Hawaii B.J. 4.

[5] See Kuhne, p. 68.

[6] Id.

[7] See Kuhne, p. 70.

[8] Jim Landers, “Trouble Impending in Patent Process,” The Dallas Morning News, May 1, 2007, p. 1D.