Expert witness testimony is critical to the pursuit of justice. There are always arcane matters that the general public and even many otherwise knowledgeable people don’t understand. That makes it impossible for a judge or jury to come to an evidence-based decision without an expert clarifying and explaining the basics of the science behind the situation. This started with forensics and got off to a bad start with bite mark evidence being used to convict a “witch” at Salem, but eventually, court rules excluded evidence that was clearly false or misleading—or at least they did for a while.
You can’t go into court today and call an astrologer to calculate the defendant’s propensity to violence from the stars or have a psychic testify that they saw you commit the crime. On the other hand, testimony has been allowed that a dog tracked a moving vehicle across busy city streets to a particular house (after the police gave the dog handler the address), and a police officer’s dream the night before was allowed as reasonable suspicion to stop a car. You will find that these extreme cases are almost always in favor of the prosecution, as judges don’t get many promotions if they are accused of being “pro-criminal.”
But sometimes, it can be hard to know if an expert is being deceptive or not, and in other cases, the expert may truly believe what they are saying but be objectively and scientifically wrong. This leads to false expert witness testimony, which should never be allowed to stand. You may say that it is up to the defense to refute the testimony, but that would be false. Two experts with reasonable opinions who disagree on a conclusion are allowed; outright false testimony should not be. Sometimes it is hard to know the difference, and I’ll give you two examples, equally ludicrous, but one is harder to distinguish without help.
Imagine you are on trial before a jury, and the case is one of negligent homicide. The law says that you can hunt on your rural property at a safe distance from inhabited structures. You were out hunting for the wild boar that has been tearing up your garden, and you took a shot at one last Tuesday. You missed, and, unfortunately for you, last Tuesday, a woman at a nearby farm was found dead of a bullet wound to the head from the same caliber as your rifle. The prosecutor found some farmhands who saw you take the shot, and you’ve been indicted. You take the stand in your defense, and here’s what you tell them.
You were using an IMI Timber Wolf pump .357 Magnum rifle to hunt for these pigs. You chose this unique firearm because you have quite a collection, and you didn’t want to use a longer range, 5.56mm or .308, to be safe, as there are farms within a half mile, including the one where the woman was found dead. You know the maximum effective range of your rifle is only about 100 yards for most people, but you were a Marine sharpshooter in your younger days, so it’s probably about 200 yards for you. You remember everything about that day and relate it to the jury.
You were about 75 yards from a large boar and, from a standing position, raised your rifle and followed your Marine training: breath, relax, aim, sight, and squeeze (BRASS). But before you felt the rifle kick, the pig turned quickly and, with the sound of the shot echoing over the valley, scampered away. You looked around a little more and went home. Later, there was a knock on the door, and you were questioned by a police officer about hearing a gunshot. You explained that you were hunting on your own land and took one shot. He wrote it down and left. You thought that was the end of it until the arrest.
The investigation had lasted months, but you were oblivious to this, going on about your life as usual. You didn’t know the woman, and you are positive that the shot that took her life didn’t come from you. The prosecutor started to come under pressure from friends and family; someone had to pay, and they hired a ballistics expert who said that it was possible that the bullet killed the woman. He gave a written opinion on the matter, plotting possible trajectories and the arc of the bullet, and convinced the prosecutor that the house was in the range of your rifle, and that was it—enough to get you indicted and arrested.
Now here you are, months later, out on bail and sitting in the courtroom, having endured the hateful glares of the woman’s family and friends and the timid looks of suspicion from your own friends, or at least those you thought were your friends. Only one or two have come by to check on you with real concern, and one of them is waiting outside the court: a hunting buddy who will testify about your excellent marksmanship and gun safety habits, about how you never load the gun until you are ready to hunt, never point it anywhere but straight up or down until you have a target, etc.
He takes the stand and says all these things, and you feel good to have such a friend, confident that you will be okay. But now it’s the prosecutor’s turn. He gets up and asks your friend if he has ever seen you become angry or violent, and he says no, that you are always cool and collected. He goes on to say that you’re nice and would never intentionally put someone’s life in danger. The prosecutor establishes that he was not there that day and has no idea what happened, and he agrees. He asks if the friend thought you were angry about the pigs destroying the garden, and he says yes, he knew you were upset about it.
You have a ballistics expert, and he explains how that type of rifle has a maximum effective range of up to 200 yards but admits that the bullet itself can go much farther—over a kilometer, in fact—so it could theoretically reach the house where the woman died. But he points out that a man standing and firing at a pig 75 yards away will be taller than the pig and firing toward the ground, making it impossible for the bullet to continue its flight more than maybe ten yards behind the pig. The police and both the defense and prosecution experts had looked for the bullet without any luck.
The prosecution gets to cross-examine and asks about you possibly flinching or jerking the trigger, which would take the bullet high and to the right—exactly the direction of the victim’s house from the direction and position you told the police you were standing when you fired. Your expert allows that it’s always possible but unlikely for a trained Marine, and, he adds with a smile, it wouldn’t matter if you had. The prosecutor asks why not, and now the defense expert lays your best argument, the proof that you are not responsible: there were no windows or bullet holes in the wall of the house where the woman died.
The prosecutor gets a smug look on his face and asks your expert if he’s familiar with quantum mechanics. He says he’s heard of it but admits that his physics classes didn’t go deeply into that area, and he does not have any expertise in this field. The prosecutor says that will be all. Now the prosecution gets to call their witnesses: someone you argued with at a local bar, who thought you seemed to have an anger problem and were about to hit him; your ex-wife, who admits that you were never violent but seemed capable of it to her.
The next expert is a ballistics expert who also has a PhD in physics. He reiterates what he said in his report, meticulously noting the same caliber of the bullet, and says that the bullet that hit the woman was too distorted for rifling examination to be dependable, something your expert had found also. He opined that your bullet had indeed killed her. “But how,” asked the prosecutor, “there was no hole in the wall!” The expert looks serious for a moment, then says, “It is not common, but a bullet can go through a wall and leave no hole.” He is asked to explain to the jury how, and this is what he says.
“It is a well-known fact of quantum physics, the single most verified scientific area of all, that this is possible. He himself has witnessed it many times in the lab. The fact that an object can move from one location to another without creating a hole in any substance between those two locations is not in doubt. This proven phenomenon is called quantum tunneling,” and he explains how while working on his PhD in physics, he performed experiments in the university lab to understand this phenomenon and to help prevent it in electronic circuits, which is where he gained his expertise, and offers to explain…
Heisenberg’s uncertainty principle creates a cloud of what can be thought of as location probability around any object. The object, let’s consider an electron, is somewhere within that cloud. The chances of finding that electron at any specific location can be calculated using Schrodinger’s equations. Simply take the time-independent Schrödinger Equation Hψ = Eψ; where H is the Hamiltonian operator representing the total energy, E is the energy eigenvalue, and ψ is the wavefunction describing the electron’s state. And use the normalizing condition: ∫ ψ*ψ dτ = 1, to determine the normalization constant.
Then use the probability density function: ρ(x,y,z) = ψ*ψ to get the probability of finding the electron in an infinitesimal volume dτ around a point (x,y,z). Armed with these equations and solutions, we calculate the probability in a given region: P(a<x<b, c<y<d, e<z<f) = ∫∫∫ ρ(x,y,z) dx dy dz, and know the probability of finding the electron in a specified region of space by integrating the probability density over that region. This is done by calculating the radial probability distribution: P(r) = r^2 * R(r)^2, where R(r) is the radial part of the wavefunction ψ. This gives the probability distribution as a function of distance r.
Finally, using the angular probability distribution, derived from the angular part of ψ involving spherical harmonics, of course, with the other factors, gives us the probability distributions for the angular coordinates. All of these calculations prove beyond any reasonable doubt,” he says, looking at the jury, “that it is indeed possible for an object, even a bullet, to pass through a wall without leaving a hole.” Your attorney tries to recall your expert to testify about this, but the prosecution objects, arguing that your witness is not an expert in quantum theory. The court agrees, and with no more witnesses, the trial is over. It’s up to the jury.
You may find this example ridiculous on its face, but in fact, everything above is absolutely true. It is indeed possible for a bullet to quantum teleport through a wall, just like electrons will teleport from one conduction strip to another through an insulator without making a hole. That’s because if the wires are close enough together, the electron’s probability wave will include that other wire, and, with a calculable frequency, the electron will teleport. Now, if you were on that jury and you knew anything about the real world, you may understand that even if this is theoretically possible, it never actually happens.
And that would be true too. The possibility of quantum tunneling decreases exponentially with increasing mass. And while it is common in electrons in the most densely packed integrated circuits today, if the entire universe were nothing but walls and .357 caliber bullets, it would not happen even once in a trillion years. So, it is practically impossible, even if the expert witness gave the jury the impression that it was actually possible. But what if we are talking about a different area of science? Most people have personal knowledge about objects and walls, but what about medicine? With its MRIs and EMGs?
An expert witness testified in the trial of a medical doctor in 2022 that the expert could look at an MRI and tell from it that the patient in question did not have the pain he had reported. Furthermore, he told the jury that the radiologist who had read the report was wrong and that the injuries were not as severe as the expert said. He went on to say that the treating physician on trial should have known these things and that his failure to do so was criminal, willful blindness to these “facts,” as he told them. He argued that all the doctors treating this patient before, who had used the same medications, were also wrong.
How many members of the general public would know if this was true or not? Even if the doctor takes the stand in his defense, as this one did, the court has accepted this “expert” and presented them to the jury as such. Any defendant in any court in the world has an uphill battle. Jurors and even judges are prone to feeling that the state would not drag you to court without cause—you must have done something. And anything a defendant says on their own behalf is easy to disregard, as someone just trying to save themselves. The prejudice of false expert witness testimony cannot be overstated.
One man was convicted of murder when an expert witness said that she could tell from a smudge on the door, not just that it came from the defendant’s boot, but that she could tell the defendant’s foot was in the boot when the door was kicked. This was allowed to stand, and the defendant stayed in prison. How do experts get this far afield, especially doctors? It starts gradually. First, a physician is flattered to be called an expert in the first few cases, and twenty years ago, they did not go after a doctor unless there was a clearly criminal act. No doctor was ever prosecuted for “an insufficient physical examination.”
Over time, the prosecution of doctors became more common, and the expert medical witnesses willing to stretch a little for the prosecution became more popular and better paid. Soon, most of their livelihood was dependent on these prosecutions, during which they would be paid hundreds of thousands of dollars a year and be jetted all over the country. Once dependent on these payments, the doctors become compromised, having lost touch with their obligation as scientists or buying into the prosecutor’s ethos that the ends justify the means, as people are prone to doing.
In the Principles and Practice of Pain Medicine, the definitive textbook on this subject, it clearly says that you cannot tell someone’s pain level from medical imaging. But the textbook cannot come to court with you. And it is impossible to anticipate every way that an expert can mislead the jury. Imaging can show the evidence of previous fractures and scar tissue, but they cannot tell you what level of pain those changes generate. But the facts don’t matter in these cases. In almost every instance, if the prosecution can lie and mislead long enough to get that conviction, they get to keep it.
I’ve seen trials where the government’s experts say that a Narcan prescription proved the doctor knew that the patient was at high risk and shouldn’t be on opiates, then in another trial, the government’s expert said that the doctor not prescribing Narcan proved that he didn’t care if the patient died. I’ve seen them criticize doctors for not using antidepressants and sleep aids when they were not prescribed, then call their use “inappropriate” in other cases. Physicians all over the country are going to prison because educated professionals who should have more integrity have put personal profit over scientific truth.
Eventually, defense attorneys will get wise and will feed all previous expert testimony from government experts into a database, cross-referenced for consistency. This is one of the uses of AI that I applaud and look forward to. But this will not help the hundreds of doctors already behind bars. Only the court’s recognition that this is a grave injustice upon which a conviction cannot stand has any hope of rescuing a fragment of truth from this ocean of injustice. And it must be retroactive. Until then, it is not safe to treat pain in the United States of America—or use any controlled medication for any purpose, for that matter.
L. Joseph Parker is a research physician.
