An ideal expert witness is neutral. A neutral expert has no financial ties to either party in a dispute, apart from being retained to provide an expert opinion. Since they have no financial interest in the outcome of a court case, juries generally regard neutral experts as more credible than experts who have a financial incentive to slant their testimony.

Courts do not generally condition the admissibility of expert testimony on an expert’s neutrality. For example, crime lab experts often work for a state or local government and invariably testify in support of prosecutors who bring criminal cases on the government’s behalf. The fact that they are employed by the party might be seen as evidence of partiality, but it does not disqualify a crime lab employee from giving testimony.

On occasion, however, the absence of neutrality suggests a conflict of interest that creates controversy. The competing roles of Dr. Jeffrey Ho provide a recent example.

Dr. Ho’s Alleged Conflicts of Interest

Jeffrey Ho carries a badge, a Taser, and a stethoscope (not necessarily at the same time). Dr. Ho is the head of paramedics at Minnesota’s Hennepin County Medical Center (HCMC). That job requires him to oversee the response that paramedics make to 911 calls.

Dr. Ho is also a part-time sheriff’s deputy in rural Minnesota. That allegiance to policing has raised ethical questions about his third job: acting as a paid advocate for Axon Enterprise, the company that manufactures Tasers.

In 2005, Axon paid Dr. Ho to write an article disputing well-documented evidence that suspects have died because the police shot them with Tasers. Dr. Ho blamed the deaths on “excited delirium,” an alleged condition that is not recognized by the American Medical Association, the American Psychiatric Association, or the World Health Organization.

Dr. Ho’s theory is that people who suffer from “excited delirium,” a condition characterized by extreme agitation and paranoia, are prone to cardiac arrest. If that is the case, Dr. Ho suggests, officers should be trained to recognize the symptoms and to avoid tasering suspects who exhibit them.

Some researchers agree that excited delirium might be an actual condition. Others find the medical evidence in support of the alleged condition to be unconvincing. The key issue, however, is whether Dr. Ho’s research results are influenced by his employment.

Axon has paid HCMC about $140,000 a year to fund Dr. Ho’s position, including his Taser research. Dr. Ho earns a salary of about $460,000 from HCMC and, according to court records, is paid as much as $70,000 a year by Axon to provide consulting services, including serving as an expert witness in cases alleging that a Taser caused a death. Dr. Ho also serves as an expert witness for law enforcement officers who are charged with causing harm by Taser use.

It isn’t unusual for industries to pay medical researchers to discount the harm caused by their products. Whether medical researchers produce reliable results when they are being paid by an industry that benefits from the research is usually a question for the jury to answer.

While Dr. Ho contends that he always declares conflicts of interest, news reports suggest that Dr. Ho’s allegiance to his fellow police officers and to Axon is not always made clear. For example, Dr. Ho contributed to a 2009 white paper that described excited delirium as “a real syndrome of uncertain etiology,” but the paper did not disclose Dr. Ho’s financial interest in helping Axon avoid liability for Taser deaths.

Dual Allegiance

Dr. Ho’s tenure at HCMC and his service as a law enforcement officer have been controversial for additional reasons. The StarTribune reported that Dr. Ho’s “dual allegiances to medicine and policing collided last summer” when investigators found that police officers were urging paramedics to sedate emotionally disturbed suspects with ketamine.

The suspects then participated, without their consent, in an HCMC study of ketamine. Dr. Ho was the lead researcher in that study. He was investigating whether ketamine counteracts excited delirium.

While HCMC’s chief executive resigned when the cozy relationship between law enforcement and HCMC was exposed, Dr. Ho has continued in his position. A member of the city council questioned whether it is appropriate for a doctor to act as an advocate for the use of weapons against potential patients.

Dr. Ho’s position is that Tasers save lives because they are less likely to be lethal than shooting a suspect with a gun. Since Tasers are usually employed against unarmed suspects, however, the question is whether less lethal alternatives to Tasers might usually be appropriate.

The bottom line is whether the controversies surrounding Dr. Ho will affect his credibility as an expert witness. The answer to that question may depend on the extent to which judges allow opposing parties to cross-examine Dr. Ho about his ketamine research, his loyalty to the law enforcement community, and his history as a well-paid consultant to the company that sells Tasers.