Your Expert Witness May Change Their Mind: Here’s What You Need To Know

A properly retained expert witness is hired to employ their training, education, and experience to review data and draw conclusions about the evidence at hand. But hiring an expert is not tantamount to purchasing their opinion. An expert should not be retained for the purpose of affirming the opinion of one side or the other. So of course, when asking whether an expert witness can change their mind, the answer is a resounding “Yes!”

Reasons an Expert May Change Their Mind

There are many reasons an expert witness may change their mind. Some examples include:

1. Advances in science
2. Advances in their understanding of evidence
3. Additional experience which leads to additional insights
4. Discovery of mathematical errors
5. New evidence
6. New perspectives based on the conclusions of other experts

When an expert discovers, or is provided with, evidence that impacts their analysis, the expert must carefully consider their conclusions to determine if they may come to a different conclusion given the new circumstances.

Reporting Obligations

When an expert has provided a report or a deposition, “[a]ny additions or changes to this information must be disclosed by the time the party’s pretrial disclosures under Rule 26 (a) (3) are due.” Fed.R.Civ.Pro. 26 (e) (2). This rule can lead to disclosures well ahead of trial, which may lead to a more or less favorable result than the parties originally anticipated. However, cases often present themselves well after the party’s pretrial disclosures are due. The change in expert opinion may come on the eve of trial, or even many years after a trial has taken place.

Criminal Cases

Some states have recently enacted laws to address the issue of newly discovered scientific evidence in post-conviction cases. Both California and Texas have passed laws allowing for new trials for cases in which relevant scientific evidence was not available at the time of trial due to:

1. Limitations in the field of scientific knowledge at the time of trial
2. Limitations in the expert’s personal scientific knowledge at the time of trial
3. Changes in the scientific method upon which the government relied since the time of the trial

In California, the Supreme Court granted a writ of habeas corpus in May of 2016 after bite mark experts recanted their testimony linking defendant Bill Richards’ teeth to marks on the body of his murdered wife. In Texas, at least one man has been granted a new trial after a forensic pathologist changed her conclusion from “homicide” to “undetermined” regarding the death of a small child. Prosecutors subsequently dropped all charges.

Civil Cases

In Pace v. Swerdlow, 519 F.3d 1067 (10th Cir. 2008), the plaintiffs sued Dr. Swerdlow, who had originally agreed to testify as their expert witness in the wrongful death of their daughter. After being deposed by the other side, which included pointed questions about his knowledge of the treating anesthesiologist’s deposition, Dr. Swerdlow expressed concern about his medical license and how he was treated by opposing counsel. He subsequently refused any contact with the plaintiffs. On the eve of summary judgment motions, Dr. Swerdlow faxed an addendum to his previous opinion, indicating he had since reviewed the treating physician’s deposition and did not find a deviation from the proper standard of care. This fax was sent to both the lawyer representing the Paces as well as opposing counsel. The case was dismissed.

Plaintiffs then sued the doctor, alleging he committed the following torts:

1. Professional malpractice
2. Fraud
3. Breach of fiduciary duty
4. Negligent misrepresentation
5. Breach of contract
6. Breach of the implied covenant of good faith and fair dealing
7. Negligent infliction of emotional distress

The District Court dismissed the claims. On appeal, the Tenth Circuit found the plaintiffs alleged facts which, if proven, may establish the necessary proximate cause to prevail against the defendant. Note: the court did not render an opinion on the ultimate issue of whether the expert did, indeed, fail in his duty towards the plaintiffs.

What are the Stakes?

When an expert witness changes their opinion, the consequences may vary based on a number of factors. For example, if the expert changes their opinion prior to issuing their report, counsel may respond accordingly with no harm to the client. Counsel may choose not to name the expert but retain them for consulting, or they may choose to hire another expert altogether.

If the expert changes their opinion after expert names and opinions have been exchanged, whether before or after being deposed, the basis for the change in opinion may dictate potential consequences. In some jurisdictions, the doctrine of absolute witness immunity is recognized. In some states, professional malpractice or some other tort action may be permissible. Whether the change in opinion is due to negligence, malpractice, malfeasance, an honest mistake, or the lawyer’s failure to provide the relevant evidence for the expert to consider may all have an impact on the viability of a lawsuit as well.

Practically speaking, however, the expert may have very little choice but to modify their opinion if additional facts and circumstances come to light. Staying silent could put an expert in the position of facing the choice between perjury charges or testifying (surprise!) to their altered conclusions for the first time on the stand. This, of course, is untenable.

Judge Neil Gorsuch (now Supreme Court Justice Neil Gorsuch) concurred in part, and dissented in part, in the Pace decision. In his opinion, he expressed a concern about lawsuits against experts, writing, in part:

Allowing this claim to march along sends the message to would be expert witnesses: Be wary—very wary—of changing your mind, even when doing so might be consistent with, or compelled by, the standards of your profession. Neither can there be any doubt this is exactly the message plaintiffs wish to send, candidly explaining, as they do, that their real beef with Dr. Swerdlow was his failure to “deliver the expert liability opinion he had promised the Paces all along.” In our legal system, demanding that experts “deliver” a specified opinion, as opposed to their honest judgment, is supposed to be ethically out of bounds – not the basis for a cause of action.

What Can An Expert Do?

Experts may wish to give careful consideration to the language in their retainer agreements. They may wish to make clear, in writing, they are making themselves available for their knowledge, expertise, and training, and that no particular result has been, or can be, guaranteed. They may further wish to add a section on circumstances wherein they reserve the right to change their opinion.