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When Do You Need an Expert Witness?

Christine Funk

Written by
— Updated on June 23, 2020

When Do You Need an Expert Witness?

When Do You Need an Expert Witness?

In many lawsuits, an expert witness is a necessary component.  Without an expert providing information on how and why something went wrong, or what the generally accepted standard of care is in their particular realm of expertise, juries may have no basis upon which to make an informed decision.  The types of lawsuits wherein experts are often used include:

  1. Business and insurance litigation, including accounting practices, banking customs, labor relations, and securities
  2. Car crashes, dealing with accident reconstruction and independent medical examinations
  3. Construction accidents, including the use of cranes and other machinery, safety programs and trainings, the proper use of scaffolds, and the correct way to dig trenches
  4. Medical malpractice claims, addressing the standard of care, proximate cause, informed consent, or the nature of a specific disease or condition
  5. Other forms of professional malpractice, to explain accounting practices, skill possessed by members of the profession, and specialized knowledge
  6. Product liability, including discussions of design flaws, product manufacturing, necessary warnings, and safety devices
  7. The issues related to damages, including lost past and future income, present cash value, lost profits, disability and disfigurement, and the permanence of injuries

Rules Regarding Expert Opinion Testimony

In federal courts, expert witness opinion testimony is governed by Federal Rule of Civil Procedure 702, which provides an expert may offer opinion testimony if their knowledge, skill, experience, training or education qualifies them to do so, and such an opinion will help the trier of fact, provided some other caveats are met.  These caveats include:

  1. The testimony is based on sufficient facts or data
  2. The testimony is the product of reliable principles and methods
  3. The expert has applied the principles and methods reliably to the facts of the case

Rules Regarding Lay Opinion Testimony

Lay opinion testimony, on the other hand, is governed by Federal Rule of Civil Procedure 701.  When someone is not testifying as an expert, they are testifying based on their own perceptions, offering information helpful to understanding the witness’s testimony or determining a fact in issue that is not based on scientific, technical, or other specialized knowledge within the scope of Rule 702.

Does All Math Require an Expert Opinion?

Regardless of any one individual’s abilities in math, mathematical calculations may or may not require an expert opinion in court.  For example, if the issue in a crash reconstruction includes a calculation involving the speed of the first car, the curve of the road, the angle of the second car stalled in the middle of the road just past the curve, and the baldness of the first car’s tires, an expert is likely needed.  This is not, however, always the case.

In United States of America, Appellee, v. Tomás Sepulveda – Hernandez, the First Circuit affirmed the introduction of mathematical calculations by a chemist under Rule 701.  The facts relevant to the issue include a drug conspiracy, wherein the amount of drugs sold was at issue.  Testimony had been elicited from others that 250 large bags of drugs and 250 small bags of drugs were sold each day for a number of years.  Calculations about the average large bag weight and small bag weight were also presented.  The prosecutor asked the chemist to perform the following multiplication:

  1. The weight of an average small bag multiplied by 250
  2. The weight of an average large bag multiplied by 250
  3. The subtotal of these amounts multiplied by 365 days in a year
  4. This sum multiplied by 9 to represent 9 years of sales

These calculations were then offered to the jury to estimate the amount of drugs sold over the life of the conspiracy.  The defendant argued the math was beyond the chemist’s field of expertise on appeal.

The First Circuit noted while the line is sometimes difficult to draw between expert and lay person opinion testimony, it was not difficult in the case at bar.  Rather, the court said, lay opinion derives “from a process of reasoning familiar in everyday life,” citing the 2000 advisory committee notes on Rule 701.  They stated further,

Simple arithmetic, such as ordinary multiplication, is a paradigmatic example of the type of everyday activity that goes on in the normal course of human existence. One does not need a graduate degree in chemistry to master multiplication: in this country, that subject is universally taught in elementary schools. Without such a rudimentary skill, ordinary tasks such as figuring a family’s budget, shopping in a supermarket, and converting a recipe for four into a meal for ten would assume Herculean proportions.

The court let the conviction stand.

Does Emotional Distress Require an Expert Opinion?

In Thornton v. Garcini, M.D., the court addressed the issue of whether an expert opinion is required to establish negligent infliction of emotional distress.  Toni Thornton gave birth on August 20, 2000.  She was attended by nurses, and the baby was in a breech position.  The child became stuck, with his body out of the vagina, and the head inside the vagina.  The infant died while in this position.  The hospital contacted the on-call Doctor, who instructed the nurses not to attempt to remove the infant, for fear the action might decapitate the child.  Plaintiff testified about her distress, remaining with the infant protruding from her vagina for over an hour before the Doctor arrived and removed the deceased child.

After a jury award, Dr. Garcini appealed, arguing plaintiff’s failure to provide expert testimony about her distress entitled him to a judgment notwithstanding the verdict.  The Supreme Court of Illinois did not agree.  Instead, they noted that while the existence of medical testimony, or lack thereof goes to the weight of the evidence, it does not prevent the plaintiff from presenting the issue to the jury.  Rather, the jury could find, based on personal experience and knowledge alone, the circumstances caused the plaintiff emotional distress.

Defendant further argued an expert was necessary in this case, because the distress felt may have been from her physical situation, or it may have been due to the death of her child.  It would be unfair, the defendant argued, to allow recovery for the death of the child.  However, the court reviewed the plaintiff’s testimony, wherein she specifically testified as to the facts of her physical condition and how this caused her distress.  In light of this, the Supreme Court upheld the award.

Does Adding a Signer to An Account Require an Expert Opinion?

In Schultz v. Bank of America, plaintiff brought claims of breach of conduct and negligence, when the bank added a name to plaintiff’s deceased father’s bank account.  The jury found in favor of the plaintiff and the bank appealed, arguing petitioner produced no expert testimony establishing the bank’s standard of care.

The appellate court noted that while almost everyone has had the experience of adding someone to a bank account, this is not the experience relevant for the case at hand.  Rather, an expert is necessary to establish the internal bank procedures relied on when deciding to add a signer to an account.  This information about professional standards in the industry is not common knowledge.  As such, the court held the trier of fact could not be expected to appreciate the bank’s standard of care without the assistance of expert testimony.  Reversed.

To Call or Not to Call, That is the Question

The decision to call, or not to call an expert witness is a challenging one.  Perhaps a sound starting point is to ask a lay person about a given situation, to see if they have a grasp on the relevant issues.  Understanding the bank procedures, which are governed by federal law and professional standards, may not be within the purview of the average lay person.  Understanding the distress of being physically attached to a deceased newborn, on the other hand, is something the general public can at least minimally appreciate without having experienced it personally.  The most cautious approach may be to err on the side of getting an expert.  However, the cost of retaining an expert can be prohibitive.  At the end of the day, discerning between common knowledge and expert knowledge is case and fact specific.

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