“Gate-keeping function.” That is what you call the judge’s role in deciding whether to allow an expert witness to testify. The judge is supposed to screen experts to make sure that what they are saying is scientifically sound. Jurors have a hard time assessing scientific evidence, and are too susceptible to believing whatever an “expert” tells them. When the judge does not properly exercise this “gate-keeping” function, all sorts of things can go wrong.
A case in point is the Jeffrey Havard conviction. After 13 years the Mississippi Supreme Court has finally conceded that Jeffrey Havard is entitled to a hearing at the trial court level on whether or not the new evidence about the expert witness Steven Hayne’s testimony warrants a new trial. In 2002, Dr. Hayne made several unsupportable conclusions about the way Havard’s girlfriend’s daughter died. He has since clarified and retracted many of the statements over the years, but this has left a 13-year mess and an innocent man still behind bars. See my prior posts about the Jeffrey Havard case here and here.
In 2002, Jeffrey Havard was charged with murder. The pathologist Steven Hayne testified that the death was caused by shaken baby syndrome. Havard’s lawyer asks for a second opinion from an independent pathologist but that request was denied. At the trial, Dr. Hayne testified: “It would be consistent with a person violently shaking a small child. Not an incidental movement of a child, but violently shaking the child back and forth to produce the types of injuries that are described as shaken baby syndrome, which is a syndrome that is known for at least 45 years now.” Years later in an interview with the Clarion Ledger, Dr. Hayne seemed to back away from that conclusion. He later prepared an affidavit for the defense team explaining: “At trial I testified that the cause of death of Chloe Britt was consistent with shaken baby syndrome. Recent advances in the field of biomechanics demonstrate that shaking alone could not produce enough force to produce the injuries that caused the death of Chloe Britt. The current state of the art would classify those injuries as shaken baby syndrome with impact or blunt force trauma.” (Thus consistent with Havard’s explanation that the child accidentally fell and hit her head.)
The change in Dr. Hayne’s testimony coincides with a shift in thinking in the medical community on the subject of shaken baby syndrome. One of the physicians who originally developed the science of Shaken Baby Syndrome published a paper in 2012 expressing concerns about the misapplication of the science. The physician, Dr. Norman Guthkelch, wrote: “While society is rightly shocked by an assault on its weakest members and it demands retribution. But there seem to have been instances where both medical science and the law have gone too far in criminalizing alleged acts of violence of which the only evidence has been the changed clinical state of the infant.” And that is pretty much the Jeffrey Havard case. Extremely shocking allegations that were deeply disturbing to the members of the jury. At his trial, the criminal defense lawyer at the time was denied funding for an independent expert. The only testimony the jurors heard was the flawed testimony of Dr. Hayne, which he later has partially recanted. An independent expert can assist a court in exercising its gatekeeping function by revealing to the judge that the opinion offered by the state’s expert is scientifically flawed.