In September, the President’s Council of Advisors on Science and Technology (PCAST) issued a scathing report on the use of forensic analysis and expertise in the criminal-justice system. The report, “Forensic Science in Criminal Courts: Ensuring Scientific Validity of Feature-Comparison Methods,” looked at pattern matching forensic disciplines such as bite mark matching, shoe print matching, blood spatter analysis, fingerprint matching and hair fiber analysis. It also looked at DNA testing when investigators find biological material from multiple sources, a scenario that can bring human subjectivity into the testing. With the exception of single-source DNA testing, the report found serious deficiencies in all areas of forensics it studied.
The PCAST report was damning, but if you’ve been following these issues with any regularity, it wasn’t at all surprising. That was in September. It’s now January. And not only has the Obama administration done nothing about the report, the Justice Department has publicly denounced it. That report, along with others and an administration that seemed unusually equipped to take it seriously, presented a small window in which to reform a system. That window is about slam shut. And we’re about to be governed by a new administration that seems likely to board it up, wallpaper it and overlay it with brick. This wasn’t just a missed opportunity; it was a catastrophe. And it’s difficult to overstate the consequences.
Nearly all the fields PCAST studied were in the field of pattern matching, in which an analyst looks at evidence from the crime scene and either draws conclusions about how the crime occurred or attempts to “match” that evidence to a suspect or suspects. The problem is that all of these fields are inherently subjective. They rely not on scientific analysis or mathematical computations but on the judgment of the analysts. This is why while you’ll frequently see two bite mark analysts or blood spatter analysts give mutually exclusive testimony in a case, you’ll rarely if ever see it among two DNA scientists (at least when the tested DNA came from a single source).
Inevitably, then, the amount of weight a jury typically gives to evidence from these fields of forensics depends far more on the persuasiveness of the expert witnesses than on the evidence itself. In fact, there’s a strong bias in favor of testimony that’s less scientific. In recent years, prosecutors and defense attorneys alike have called attention to the “CSI Effect,” the way the popular TV franchise has conditioned jurors to look for forensic evidence that’s definitive and foolproof. Most forensic evidence isn’t completely clear cut. It’s merely suggestive. So a forensic analyst who gives testimony properly grounded in science will be careful not to speak in absolutes, will use cautious and careful language — and will be far less successful at persuading juries. The analysts who gleefully gallop past scientific boundaries in a rush to implicate suspects are far more successful in the courtroom. Because prosecutors and defense attorneys want to win cases, many will opt for the analysts who give them the best chance to do so. The quacks rise to the top.
There are other problems, too. With the exception of DNA testing and to some extent forensic pathology, most forensics fields were invented and developed by people with backgrounds in law enforcement, not in science. This is why crime labs, which claim to be scientific in nature and method, typically fall under the auspices of state police agencies, offices of the attorney general, departments of public safety and other law-enforcement-oriented bureaucracies. So not only has forensics grown less scientific over time, it was never grounded in science to begin with. DNA was discovered by scientists. Consequently, we know the frequency with which certain DNA markers appear across the human population. This is why a DNA analyst can give precise calculations of the odds of the suspect being the person whose DNA was left at the crime scene or in the rape victim. (Again, provided we’re talking about cases in which there was only one source for the DNA.) Put a different way, DNA analysts can provide an error rate — a calculation of the chances that the match is mistaken. (It’s usually an extremely low number.)
Pattern matching analysts can’t do that. When analysts look at the characteristics of hair fibers to distinguish one from another, we don’t know the rate at which those characteristics are distributed across the population. The same goes for distinguishing the features analysts look for in bite marks. It’s even true of fingerprints.
With many pattern-matching fields, the material in or on which the data is recorded presents an added problem. Even if we could somehow prove that everyone’s bite is unique, there’s no scientific evidence to support the notion that human skin is capable of recording those unique features in a usable way. (The existing research strongly suggests the opposite.) There are just too many variables. The victim may have been pulling away as the bite was inflicted. The wound could have been corrupted by heat, cold, insects or any number of other things. People heal differently, and the elasticity, sponginess and toughness of skin varies from person to person, and even on different parts of the same person. There’s the angle at which the biter struck, whether the biter drug his teeth or bit straight down, and so on. The same goes with tire or shoe marks in dirt or mud, blood spatter patterns and so on. There are too many variables that could affect how these patterns are recorded and preserved.
Nevertheless, these fields have been used over and over in court. Because these disciplines were developed outside the field of science, and because science and law tend to mix like oil and water, it has taken a while for scientists to catch up, and to test the claims of forensic analysts. It was really DNA testing that began to expose the flaws in forensic analysis, as testing began to overturn convictions that forensic expert witnesses had testified were rock-solid.
The aim of the PCAST report, as well as the 2009 National Academy of Sciences report and the National Institute of Standards and Technology working groups,was to bring science to forensics — or rather to see if there’s any science behind the claims of forensic analysts. The 19 PCAST members are all scientists. While some legal experts did provide some guidance, the evaluation itself was done by some of the most eminent scientists in the country. These weren’t defense attorneys or social justice activists.
What PCAST, NIST and the NAS have found, overwhelmingly, is that all pattern matching fields of forensics lack any scientific support for their basic assumptions. The Obama administration seemed to understand these problems like no administration to date. Obama himself along with former attorney general Eric Holder have openly acknowledged that the criminal-justice system is flawed and in need of reform. In July 2015, Jo Handelsman, the assistant director of the White House Office of Science and Technology Policy, called for the eradication of bite mark evidence in court. It’s the Obama administration that oversaw the creation of the NIST working groups to study the validity and reliability of various forensic disciplines. And it was obviously Obama’s own PCAST that produced the paper last year in the first place. The White House even put out a news release touting the report.
And yet when the PCAST study came out, Attorney General Loretta Lynch immediately dismissed it, stating that while “we appreciate their contribution to the field of scientific inquiry, the department will not be adopting the recommendations related to the admissibility of forensic science evidence.” Lynch joined the National District Attorneys Association and various police organizations in casting the study as no big deal.
There are a number of reasons why it is in fact a big deal. First there’s the FBI, which Lynch oversees. Obviously, if the FBI crime lab isn’t going to make changes in the face of these reports, that’s going to affect the quality of the forensic evidence used in federal criminal cases. But the FBI crime lab also does forensics work for local police and prosecutors across the country, so those cases will also be affected. FBI crime lab analysts train state and local analysts, so the bad methods are passed on. The FBI crime lab is also generally seen as the preeminent crime lab in the country, so other crime labs emulate it. If the FBI isn’t going to change in the face of overwhelming scientific evidence, why should anyone else?
Then there’s the matter of the FBI’s own record. . .
Loretta Lynch is, unfortunately, clearly incompetent in her job. Meeting privately with Bill Clinton when there is a case pending against his wife? That seems to show very poor judgment, but it is possible that the cause was incompetence: she didn’t know how to prevent the meeting.
And her decision her is obviously extremely poor judgment, but it may be facilitated by a more general incompetence.
She is unsuited for the post she holds, though that of course is true of others.
Do read the rest of the article. There’s a lot more and it is quite serious: in cases still to be heard, the failings of current forensics “science” will send innocent men and women to prison for years if not decades, just as it has in the past. That Loretta Lynch could summarily dismiss this shows either incompetence or incredible mean-spiritedness and even bad intentions (deliberately avoiding a recommended action in the knowledge that the decision will result in the suffering of innocents).
This is very difficult for me to understand. And so I see I also cannot understand how Democrats think.