{"id":599743,"date":"2023-01-21T06:49:30","date_gmt":"2023-01-21T12:49:30","guid":{"rendered":"https:\/\/news.sellorbuyhomefast.com\/index.php\/2023\/01\/21\/fighting-murder-convictions-that-rest-on-shoddy-stats\/"},"modified":"2023-01-21T06:49:30","modified_gmt":"2023-01-21T12:49:30","slug":"fighting-murder-convictions-that-rest-on-shoddy-stats","status":"publish","type":"post","link":"https:\/\/newsycanuse.com\/index.php\/2023\/01\/21\/fighting-murder-convictions-that-rest-on-shoddy-stats\/","title":{"rendered":"Fighting murder convictions that rest on shoddy stats"},"content":{"rendered":"<div data-interstitial=\"2\">\n<div>\n<div>\n<p><img decoding=\"async\" src=\"http:\/\/www.science.org\/cms\/asset\/4e90f30c-0f64-462a-9da2-3099288adfd4\/science.2023.379.issue-6629.cover.gif\" alt=\"issue cover image\"><\/p>\n<\/div>\n<div>\n<p><span>A version of this story appeared in Science, Vol 379, Issue 6629.<\/span><a href=\"http:\/\/www.science.org\/doi\/epdf\/10.1126\/science.adg6746\" title data-toggle=\"tooltip\" data-offset=\"0,14px\" data-original-title=\"DOWNLOAD PDF\"><i aria-hidden=\"aria-hidden\"><\/i><span>Download PDF<\/span><\/a><\/p>\n<\/div>\n<\/div>\n<p><span>LEIDEN, THE NETHERLANDS\u2014<\/span>When a Dutch nurse named Lucia de Berk stood trial for serial murder in 2003, statistician Richard Gill was aware of the case. But he saw no reason to stick his nose into it.<\/p>\n<p>De Berk was a pediatric nurse at Juliana Children\u2019s Hospital in The Hague. In 2001, after a baby died while she was on duty, a colleague told superiors that De Berk had been present at a suspiciously high number of deaths and resuscitations. Hospital staff immediately informed the police. When investigators reexamined records from De Berk\u2019s shifts, they found 10 suspicious incidents. Three other hospitals where De Berk had previously worked added another 10. The probability of such a pattern happening by chance was one in 7 billion, the police said. De Berk was arrested on 13 December 2001, suspected of murdering five children. Newspapers called her a \u201cmurder nurse\u201d and an \u201cangel of death.\u201d<\/p>\n<p>Gill, then working as a statistics professor at Leiden University, remembers his wife telling him about a \u201cwitch trial\u201d and saying, \u201cThey\u2019re using statistics; you should get involved, do something useful.\u201d But Gill knew the statistician working on the case and considered him a decent, careful person. \u201cSo I thought I didn\u2019t have to. And anyway, I was obsessed with quantum mechanics,\u201d he says. In 2003, De Berk was found guilty of four murders and three attempted murders and sentenced to life in prison. An appeals court convicted her again in 2004. The Dutch Supreme Court upheld the conviction 2 years later.<\/p>\n<p>It wasn\u2019t until late 2006, when Gill read two whistleblowers\u2019 account of the trial, that he started to look into the case\u2014and became incandescent. Tunnel vision, bad statistics, and poor human intuitions about coincidence had marred the investigation. When Gill ran the numbers himself, he found the string of deaths on De Berk\u2019s watch might well be entirely due to coincidence. Along with fellow statisticians, whistleblowers, and others, Gill campaigned for a retrial that eventually led to De Berk\u2019s exoneration in 2010. Her case is now considered one of the worst miscarriages of justice in the Netherlands.<\/p>\n<p>It also opened a new chapter in Gill\u2019s professional life: He became a leading expert on the statistics of medical murder cases similar to De Berk\u2019s\u2014and a loud, persistent voice warning of the shoddy statistics that are sometimes central to prosecutors\u2019 arguments. \u201cIn a normal murder case, you actually have a body which has clearly been murdered,\u201d he says. When there\u2019s only a suspicious cluster of deaths, investigators may assume a murderer is at work and selectively focus on evidence that supports that assumption. People\u2019s intuition of an \u201cimpossible coincidence\u201d joins the dots in the evidence.<\/p>\n<p>Gill worked with defense lawyers and campaigned\u2014in vain\u2014to overturn the conviction of British nurse Ben Geen, found guilty in 2006 of two murders and 15 counts of grievous bodily harm. He also helped secure the October 2021 acquittal of nurse Daniela Poggiali, accused of two murders in a high-profile case in Italy. By now, the misuse of statistics has drawn enough attention that prosecutors sometimes insist their evidence is not statistical, Gill says, but often, \u201chidden statistics\u201d seep into the cracks.<\/p>\n<p>In a report peer reviewed and distributed by the Royal Statistical Society (RSS) in September 2022, Gill and colleagues detailed the <a href=\"https:\/\/rss.org.uk\/news-publication\/news-publications\/2022\/section-group-reports\/rss-publishes-report-on-dealing-with-uncertainty-i\/\">statistical missteps in past medical murder trials<\/a> and made recommendations for how legal systems can do better. Gill hopes the report will help with the case of another British nurse, Lucy Letby, who is now on trial for the alleged murder of seven babies and attempted murder of 10 more in a neonatal unit at the Countess of Chester Hospital.<\/p>\n<div>\n<p><img decoding=\"async\" src=\"http:\/\/www.science.org\/pb-assets\/images\/styleguide\/quotation-mark-1672180580783.svg\" alt=\"quotation mark\"><\/p>\n<p>In a normal murder case, you actually have a body which has clearly been murdered.<\/p>\n<ul>\n<li><strong>Richard Gill<\/strong><\/li>\n<li>Leiden University<\/li>\n<\/ul>\n<\/div>\n<p>\u201cSimilar issues have arisen across many, many different jurisdictions,\u201d says criminologist William Thompson, professor emeritus at the University of California, Irvine, and a co-author of the RSS report. \u201cThe same investigative dynamics play out \u2026 the same cognitive biases, and the tunnel vision.\u201d Gill likes to point out such errors with an outspokenness that frequently ruffles feathers, says statistician Peter Gr\u00fcnwald of the Center for Mathematics and Informatics, a friend and colleague who also campaigned for De Berk\u2019s retrial. \u201cHe will give very radical opinions. \u2026 But somehow he\u2019s a very pleasant person to disagree with.\u201d<\/p>\n<p><span>GILL HAS NOT ALWAYS<\/span>\u00a0been a troublemaker. His career has been defined by long detours into the bowels of arcane mathematical problems. Injustice bothers him\u2014but so does error. He spends a lot of time debating quantum mechanics \u201ccrackpots\u201d on the internet.<\/p>\n<p>Gill had a serene childhood in the English countryside. His father, a physicist, spent his career in industry. His mother, Gill discovered after World War II intelligence was declassified in 1974, had been one of the human \u201ccomputers\u201d who helped crack Germany\u2019s Enigma code at an outstation of Bletchley Park. \u201cI wasn\u2019t surprised,\u201d he says. \u201cI always thought I got my brains as much from her as from my father.\u201d<\/p>\n<p>At the University of Cambridge, where he studied math, it was statistics that most captured his attention. It had \u201cweighty ethical and philosophical implications,\u201d he says. \u201cIt was a branch of mathematics that really means something.\u201d<\/p>\n<p>As a student, he was not much of an activist. He says he feels guilty about not speaking up more about injustice when he was young. One incident in particular haunts him: his role as a statistician in a 1970s experiment that severed the front legs of rats to investigate whether bipedalism reshaped their skulls. \u201cWhat upset me most is that I didn\u2019t have the strength of character to refuse to do that job.\u201d<\/p>\n<p>The study was one of Gill\u2019s first assignments as a statistical consultant at what is now the Center for Mathematics and Informatics in Amsterdam. Newly married, with three children born in quick succession, his most pressing concern was finding and keeping a good job, and the variety of consulting projects at the center fit neatly with his desire to do something practical. He obtained a Ph.D. on the mathematical underpinnings of \u201csurvival analysis,\u201d the study of the expected time until an event\u2014such as a mechanical failure or a death in a clinical trial\u2014occurs. Later, statistical problems in quantum mechanics were his main focus.<\/p>\n<p>And then he started to look into the story of Lucia de Berk.<\/p>\n<figure>\n<div>\n<p><img decoding=\"async\" src=\"http:\/\/www.science.org\/do\/10.1126\/science.adg7536\/files\/_20230120_nf_med_mas_murd_lucia_anddaughter.jpg\" alt=\"Lucia de Berk hugs her daughter\"><\/p>\n<p><img decoding=\"async\" src=\"http:\/\/www.science.org\/do\/10.1126\/science.adg7536\/files\/_20230120_nf_med_mas_murd_lucia.jpg\" alt=\"Lucia de Berk hugs Metta de Noo surrounded by cameras\"><\/p>\n<\/div><figcaption><span>Lucia de Berk embraces her daughter Fabi\u00ebnne (first image) and whistleblower Metta de Noo (second image) after being exonerated in 2010. De Berk spent more than 6 years in prison. <span>(First image to second image) Vincent Jannink\/ANP\/Redux; ROB VOSS\/ANP\/REDUX<\/span><\/span><\/figcaption><span><\/span><\/figure>\n<p><span>DE BERK\u2019S CASE<\/span>\u00a0became famous for a number: one in 342 million. That was the probability that the many \u201cincidents\u201d on her shifts were due to random bad luck, according to Henk Elffers, a law psychologist then at the Netherlands Institute for Crime and Law Enforcement and an expert witness for the prosecution. His figure was less stark than the police\u2019s one in 7 billion, but still very damning.<\/p>\n<p>Elffers\u2019s reasoning was controversial and came under fire from statistical experts during De Berk\u2019s appeals. He had multiplied the probability of De Berk\u2019s pattern of death across multiple wards. This would make any nurse look guiltier with each job change. For example, even a mundane one in 20 chance at one hospital, and the same chance at the next, would transform into a more suspicious one in 400 chance.<\/p>\n<p>But prosecutors had additional evidence: Investigators had found traces of the heart medication digoxin in the body of one alleged victim and an overdose of the sedative chloral hydrate in another. With this evidence of foul play, a court ruled in De Berk\u2019s first appeal, other deaths could be safely attributed to her with weaker evidence\u2014such as the overall \u201cpattern\u201d of incidents, and her diary, which spoke of her \u201cvery great secret\u201d and \u201ccompulsion.\u201d The appeal was essentially a retrial and the new court convicted De Berk again, adding three additional murders to her count. De Berk, who suffered a stroke 5 days after her failed second appeal, maintained her innocence throughout.<\/p>\n<p>That might have been the end of the case if it hadn\u2019t been for Metta de Noo, a geriatrician who had inside information. De Noo\u2019s sister-in-law was the head pediatrician at Juliana, where De Berk worked, and had aided the police investigation. But when De Noo examined documents from the case, she found what she believed were flaws in the medical evidence. The infant who had allegedly died of digoxin poisoning had been declining for days after heart surgery. And the hospital had prescribed the maximum dose of chloral hydrate for the other child, allowing additional doses if needed. De Berk had been agitating for doctors to pay attention to the child\u2019s deteriorating condition.<\/p>\n<p>When De Noo asked specialists for support, she met with hostility and ridicule. Her doggedness destroyed her good relationship with her brother and his wife. She eventually turned to Ton Derksen, her other brother and a philosopher of science who had spent his career writing about flaws in reasoning of the type that permeated the De Berk investigation.<\/p>\n<p>With De Noo\u2019s help, Derksen published a bombshell book in 2006:\u00a0<cite>Lucia de B.: Reconstruction of a Miscarriage of Justice<\/cite>. (In the Netherlands, suspects\u2019 last names are commonly withheld to protect their privacy.) Derksen dismantled the figure of one in 342 million, giving a meticulous account of statistical errors, weak medical evidence, and bias in the investigation. For example, investigators examining the \u201cincidents\u201d connected with De Berk had classified deaths and resuscitations as suspicious when she was on duty, and not suspicious when she was off.<\/p>\n<p>The prosecution had also argued that De Berk\u2019s ward had seen a total of five deaths between 1996 and 2001, and all had occurred after De Berk had started working in 1999. But the ward had a different name until 1999, and earlier deaths were excluded, Derksen found. In reality, there were seven deaths in the 3 years before De Berk joined and six in the 3 years after. (De Noo published her own account of the case\u2014and the way it tore her family apart\u2014in 2010.)<\/p>\n<p>Gr\u00fcnwald, then a young assistant professor, brought Derksen\u2019s book to Gill\u2019s attention and asked whether he would join a campaign for De Berk\u2019s case to be reopened. Gill says reading the book made him \u201cabsolutely furious\u201d with himself for trusting Elffers and not getting involved earlier. And he was angry that the appeals court had claimed its verdict did not rely on statistics: \u201cTon Derksen showed that it was soaked in statistics.\u201d<\/p>\n<p>Gill quickly reanalyzed the data himself. In a write-up posted online in January 2007, he reported a <a href=\"http:\/\/www.math.leidenuniv.nl\/~gill\/elfferscorrected.pdf\">much less outlandish probability of one in 100,000<\/a>\u2014even before removing biases in the data. Gill has refined his analysis over the years, building in complexities such as the fact that nurses could be expected to have different mortality rates based on their skill, choices, and work patterns. In a paper in\u00a0<cite>Chance<\/cite>\u00a0in 2018, he and colleagues calculated a probability of <a href=\"https:\/\/www.tandfonline.com\/doi\/abs\/10.1080\/09332480.2018.1549809?journalCode=ucha20#:~:text=The%20trial%20of%20the%20Dutch,incorrect%20calculations)%20extremely%20small%20probabilities\">one in 49<\/a>.<\/p>\n<figure><figcaption>\n<h3>A murderous nurse at work\u2014or just coincidence?<\/h3>\n<p>Cognitive biases can easily lead an investigation astray and have drastic effects on how suspicious a cluster of deaths seems. In this imaginary example drawn from real-world errors, a doctor reports that many deaths seem to occur while Nurse X is on duty. The hospital launches an investigation, reexamining deaths at Nurse X\u2019s ward over the past 2 years. A simple statistical test* compares the rate of suspicious deaths when Nurse X is on duty with the rate when she is off. It then calculates the probability of seeing this pattern purely as a result of random chance.** The outcome depends greatly on the type of investigation.<\/p>\n<\/figcaption><img decoding=\"async\" src=\"http:\/\/www.science.org\/do\/10.1126\/science.adg7536\/files\/_230127_nf_massmurders.svg\" alt=\"graphic showing types of investigation and bias level\"><figcaption><span><span>C. BICKEL\/<cite>SCIENCE<\/cite><\/span><\/span><\/figcaption><\/figure>\n<p>In 2007, convinced of De Berk\u2019s innocence, Gill organized a petition to reopen the case. His quantum mechanics work was \u201cuseful after all,\u201d he says, because he persuaded Nobel Prize\u2013winning physicist Gerard \u2019t Hooft to sign, which generated headlines. But in other ways Gill was less diplomatic. He called some doctors \u201ccriminals\u201d and said \u201coutrageous things\u201d to journalists, Gr\u00fcnwald says: \u201cMetta, Ton, and I basically had to hold him back.\u201d Haga Hospital even threatened to sue him after he posted previously unpublished details about the case on his website.<\/p>\n<p>Yet Gr\u00fcnwald says Gill\u2019s cheerful fearlessness was crucial. Many Dutch statisticians knew and liked Elffers, he says. \u201cPeople \u2026 were afraid to say out loud that he was doing something stupid and nonsensical. Richard had no problems with that at all.\u201d (Elffers did not respond to multiple requests for comment.)<\/p>\n<p>The efforts paid off. In 2006, the Commission for the Evaluation of Closed Criminal Cases decided to reconsider the case and appointed a subcommittee to investigate. In a \u201cdrab government building\u201d in The Hague, Gill helped explain how bungled statistics had put De Berk in prison. In 2007, the commission recommended reopening the case; in 2008, the Dutch Supreme Court agreed. That same year, the Dutch government suspended De Berk\u2019s sentence and she was released from prison, pending a retrial.<\/p>\n<p><span>THE MISTAKES\u00a0<\/span>in De Berk\u2019s case were far from unique, Gill and others say. \u201cWe humans are terribly good at seeing patterns when they\u2019re not there,\u201d says statistician Peter Green, a professor emeritus at the University of Bristol and one of the RSS report\u2019s authors.<\/p>\n<p>Investigators sometimes enhance those patterns by only tallying the evidence that confirms their theory, discarding or not even noticing data that don\u2019t. Even investigators who aim to be unbiased can make minor choices that add up to a skewed picture, Thompson says. \u201cYou end up with a piece of evidence that looks extraordinarily unlikely to have occurred by chance. And of course, the problem is it didn\u2019t exactly occur by chance\u2014you kind of helped it along.\u201d<\/p>\n<p>Gill worries this is what led to the 2006 conviction of Geen, who was given 17 life sentences, with a minimum term of 30 years. Prosecutors argued there was a high rate of unexplained respiratory arrests\u2014which are typically rarer than cardiorespiratory arrests\u2014on Geen\u2019s shifts, although they did not try to quantify the probability that this \u201cunusual pattern\u201d occurred by chance. As in De Berk\u2019s case, there was other evidence, including the fact that Geen had in his pocket a syringe containing muscle relaxant when he was arrested. The prosecution argued that he had injected patients with the drug in order to cause respiratory arrest and then play the hero by resuscitating them.<\/p>\n<p>Geen\u2019s defense lawyers challenged the \u201cunusual pattern\u201d in a 2009 appeal, submitting a report by University of Warwick medical statistician Jane Hutton. The appeal judges upheld the conviction. \u201cThe judges seemed to be very overconfident that they could detect an unusual pattern without putting in some of the most basic information that you need as a comparison,\u201d Hutton says.<\/p>\n<div>\n<p><img decoding=\"async\" src=\"http:\/\/www.science.org\/pb-assets\/images\/styleguide\/quotation-mark-1672180580783.svg\" alt=\"quotation mark\"><\/p>\n<p>We humans are terribly good at seeing patterns when they\u2019re not there.<\/p>\n<ul>\n<li><strong>Peter Green<\/strong><\/li>\n<li>University of Bristol<\/li>\n<\/ul>\n<\/div>\n<p>In a 2022 paper published in\u00a0<cite>Laws<\/cite>, Gill and colleagues argued that blinded investigators might have reached different conclusions about Geen\u2019s case. The high rate of respiratory arrests on his shifts was accompanied by a drop in cardiorespiratory arrests, suggesting a bias in how these cases were classified. Compared with data from the same hospital over a wider time period, the deaths and resuscitations on Geen\u2019s shifts do not seem extraordinary, Gill and his co-authors said. He and other statisticians wrote letters of support in 2015 when Geen asked the Criminal Cases Review Commission to look into his case. The request was denied; Geen remains in prison.<\/p>\n<p><span>EVEN WHEN\u00a0<\/span>statistical experts do get involved in a case, they may not be immune to errors of reasoning, as Elffers\u2019s work showed. In the case of Poggiali, the Italian nurse, statisticians wrote that a very high level of statistical significance is a \u201cguarantee\u201d that \u201cthere is a causal effect\u201d\u2014in this case between Poggiali being on duty and the deaths. But this is a well-known error of reasoning: \u201cCorrelation is not causation,\u201d Green says. Thompson says clusters may have surprising causes that are difficult or impossible to uncover. He points to cases where chemicals leached from equipment or changes in baby formula were at fault.<\/p>\n<p>Gill and his colleagues found that Poggiali\u2019s death rate was higher than her colleagues\u2019, even after various controls, but argued this could be at least partly explained by Poggiali\u2019s long hours\u2014she arrived very early and left late from her shifts\u2014which meant she was present at more death certifications during shift handovers. They also pointed out a statistical flaw in the medical evidence: A toxicologist had said the potassium concentration found in one of the victim\u2019s eyes was unexpectedly high, suggesting potassium chloride poisoning. But this did not take into account any <a href=\"https:\/\/academic.oup.com\/lpr\/article-abstract\/20\/3\/169\/6696195?redirectedFrom=fulltext\">statistical uncertainty in the data on expected levels of potassium<\/a>, Gill and colleagues wrote in a 2021 paper in\u00a0<cite>Law, Probability and Risk<\/cite>\u00a0summarizing the findings that had helped secure Poggiali\u2019s acquittal.<\/p>\n<p>The Letby case now in court shows many of the same troubling features as earlier cases, Gill and others say. Letby was moved to clerical duties in 2016 after a series of deaths and resuscitations on her shifts, and first arrested in 2018. She is accused of murdering seven babies and attempting to murder 10 more, using methods such as insulin poisoning and injection of air bubbles.<\/p>\n<p>The similarities go beyond statistics to the way Letby has been vilified. Social media commentary will \u201cmake your stomach turn,\u201d Gill says. \u201cPeople are saying we should bring back hanging, shoot the bitch.\u201d The media have portrayed her as an \u201cevil creature,\u201d says Neil Mackenzie, a lawyer based in Edinburgh, Scotland, who specializes in medical negligence cases and co-authored the RSS report. \u201cI think there\u2019s possibly misogyny in there,\u201d Mackenzie says. \u201cThe press loves bad women.\u201d<\/p>\n<p>The RSS report Gill and others published in September does not claim Letby is innocent, in part because public comment on the guilt or innocence of a person standing trial may be considered contempt of court in U.K. legal systems. \u201cWe\u2019ve got to have no opinion on this case,\u201d Green says, but \u201cthere\u2019s potential here for miscarriage of justice.\u201d<\/p>\n<p>Gill says a deep cognitive bias works against defendants like Letby. People \u201cdon\u2019t believe in chance, actually,\u201d he says. \u201cQuantum mechanics has been shouting at us for 100 years that the physical universe is built on randomness. \u2026 But we don\u2019t understand this. It upsets us deeply. When a succession of bad things happens, we know there must have been an agent responsible. And so we naturally believe in devils and witches, gods and angels.\u201d<\/p>\n<figure>\n<div>\n<p><img decoding=\"async\" src=\"http:\/\/www.science.org\/do\/10.1126\/science.adg7536\/files\/_20230120_nf_medmasmurd_shipman_irene-turner.jpg\" alt=\"police exhume the body of Irene Turner\"><\/p>\n<p><img decoding=\"async\" src=\"http:\/\/www.science.org\/do\/10.1126\/science.adg7536\/files\/_20230120_nf_medmasmurd_shipman_biankapomfret.jpg\" alt=\"Grave in cemetery recently dug up to search for evidence\"><\/p>\n<\/div><figcaption><span>Police exhumed several bodies in Hyde, England, to search for evidence against physician Harold Shipman, who was convicted of killing 15 patients in 2000. <span>(First image to second image) Alamy Stock Photo; INDEPENDENT\/ALAMY STOCK PHOTO<\/span><\/span><\/figcaption><\/figure>\n<p><span>NOT ALL MEDICAL MURDER\u00a0<\/span>cases are witch hunts, however. \u201cThis is an instance where there actually are some witches,\u201d Thompson says.<\/p>\n<p>In 2000, for example, a British physician named Harold Shipman was convicted of murdering 15 patients over a period of 3 years after an investigation yielded evidence that he had given overdoses of diamorphine\u2014heroin, used in the United Kingdom for severe pain\u2014and falsified the medical records of numerous patients, suggesting they had been sicker than they were to make their deaths appear less suspicious. (Shipman was in one patient\u2019s will but his motives have not become clear.) Shipman, who is suspected of killing hundreds more, was sentenced to life in prison and died by suicide in 2004.<\/p>\n<p>A 5-year government inquiry in the wake of the case identified ways to better protect patients, such as more oversight of death certificates. The case also led statisticians to explore a new question: Could statistics detect real murderers, based on a suspicious pattern of deaths alone?<\/p>\n<p>Cambridge statistician David Spiegelhalter, who gave advice to the panel, believes so. He and his colleagues adapted a method from industrial quality control to compare the rate of death certificates signed by Shipman over time with deaths at other local doctors\u2019 practices. They found they could have identified a worrying pattern in Shipman\u2019s patients 13 years before he was arrested.<\/p>\n<div>\n<p><img decoding=\"async\" src=\"http:\/\/www.science.org\/pb-assets\/images\/styleguide\/quotation-mark-1672180580783.svg\" alt=\"quotation mark\"><\/p>\n<p>This is an instance where there actually are some witches.<\/p>\n<ul>\n<li><strong>William Thompson<\/strong><\/li>\n<li>University of California, Irvine<\/li>\n<\/ul>\n<\/div>\n<p>Such a system would produce false alarms; more people might die under the care of a doctor or nurse who works with particularly difficult cases, for example. But a robust method would prevent too many misfires, Spiegelhalter says, and a \u201cping\u201d in the system should never be taken as anything more than a sign that a human should look at the data.<\/p>\n<p>But implementing this kind of routine monitoring would be very complicated, says Bruce Guthrie, professor of general practice at the University of Edinburgh. The kind of data Spiegelhalter and his colleagues used is not routinely collected\u2014it was pieced together as part of the Shipman investigation. And Shipman worked alone, which few family doctors do; many patients are likely to see multiple doctors. Only the \u201cmost horrendously prolific murderers\u201d would be likely to show up, Guthrie wrote in an email to\u00a0<cite>Science<\/cite>.<\/p>\n<p>Meanwhile Thompson, Gill, and others are calling for cultural and institutional fixes to prevent unjust convictions. Many lawyers find statistics challenging, Mackenzie says. \u201cThis is one of the evils of the \u2018two cultures\u2019 myth,\u201d he says: Some students are channeled into scientific subjects, and others into humanities, and \u201cnever the twain shall meet.\u201d Niamh Nic Daeid, a forensic science researcher at the University of Dundee, says she routinely encounters anxiety and resistance about statistics. Nic Daeid, Spiegelhalter, and others have produced a range of statistics training materials, including an RSS \u201cprimer\u201d and a free online course for lawyers.<\/p>\n<p>But training is not enough, Thompson says, because the biases that underlie errors are \u201cbuilt into our perceptual processes.\u201d Instead, he says, it\u2019s crucial to change investigative procedures. The RSS report recommends that investigators be blinded. For example, pathologists should classify deaths as suspicious or not without knowing which medical personnel were in attendance, adapting the standardized blinding methods used in epidemiology to study disease outbreaks.<\/p>\n<p>But blinding has proved to be a hard sell among forensic scientists, in part because it\u2019s often more challenging than it seems, says Peter Stout, CEO of the Houston Forensic Science Center and a strong advocate of blinding and other measures to improve forensic science. It can mean, for example, that a forensics lab\u2014already strapped for funding and time\u2014needs an extra person to serve as a case manager who screens possibly biasing information from a blinded analyst. And the line between relevant and irrelevant information is not always clear.\u00a0Decades ago, before opioids were rampant in the United States, Stout and his colleagues spent weeks running every test they could think of on a sample, before an investigator finally told them to look for fentanyl. \u201cMasking created a huge cost,\u201d he says.<\/p>\n<p>Adele Quigley-McBride, a cognitive bias researcher at Duke University, trains analysts in a technique called sequential unmasking. The method gets around the blurred line between relevant and irrelevant information by giving investigators access to increasing amounts of information with each round of analysis. Analysts note their observations and conclusions in each round; if new information changes their opinion, they have to explain why.<\/p>\n<p><span>GILL WAS AT THE COURT\u00a0<\/span>of appeals in Arnhem in 2010 when De Berk\u2019s exoneration was announced. \u201cIt was one of the biggest events of my life,\u201d he says. \u201cIt was really joyful.\u201d De Berk was immediately rushed off by her lawyers and journalists swarmed Derksen and De Noo. \u201cI bought a marijuana cigarette,\u201d Gill says, and then he took a train to The Hague and went to the beach. \u201cI smoked my joint, and I ate a dish of oysters, and drank some white wine.\u201d<\/p>\n<p><strong><\/strong>De Berk later received a written apology from the Dutch minister of justice and an undisclosed financial compensation for the 6.5 years she spent in prison. Gill stays in contact with her; she likes his posts on Facebook sometimes. She told Gill she did not want to be interviewed for this story. \u201cShe\u2019s managed to put it all far away, and she needs to keep it that way,\u201d he says.<\/p>\n<p>Thirteen years on, Gill, now retired, is watching the Letby case closely, but his obsession with forensic statistics has begun to subside. His retirement projects include a range of statistical kerfuffles with lower stakes, such as the rating of Dutch herring sellers. He has plenty of other things to occupy his attention\u2014winemaking, an amateur distillery, grandchildren. \u201cI think I\u2019ve reached the point where I want to spend more time in the forest picking mushrooms, actually,\u201d he says.<\/p>\n<p>He hopes younger statisticians will feel compelled to help when bad statistics lead to injustice, as he did. \u201cI sensed that in the Lucia case, I could make a difference,\u201d Gill says. \u201cAnd that therefore I must.\u201d<\/p>\n<div>\n<p><span>Related story<\/span><\/p>\n<h2><span>An Australian mother lost four babies in 10 years. Did she kill them?<\/span><\/h2>\n<p><span>By <a title=\"Cathleen O\u2019Grady\" href=\"http:\/\/www.science.org\/content\/author\/cathleen-o-grady\">Cathleen O\u2019Grady<\/a><\/span><\/p>\n<div>\n<p>Next month, a judge in Sydney will hear new expert testimony in a criminal case that has fascinated Australia for 2 decades: that of Kathleen Folbigg, who in 2003 was convicted of the murder of three of her infant children and manslaughter in the death of the fourth.<\/p>\n<p>There is no medical evidence that Folbigg\u2019s children were murdered. Her case rests <a href=\"https:\/\/www.nature.com\/articles\/d41586-022-03577-9\" target=\"_blank\" rel=\"noopener\">partly on the vanishingly small chance<\/a> that unexplained medical tragedy would strike the same family four times. Like some other infanticide cases, it parallels the murder convictions of doctors and nurses based on suspicious clusters of patient deaths. As those cases show, seemingly common-sense statistical assumptions can mislead\u2014with horrifying consequences.<\/p>\n<p>Folbigg\u2019s children all died between 1989 and 1999, at ages between 19 days and 19 months. Her husband reported Folbigg to the police after discovering her diary, in which she had described anger and frustration with her children, and a sense of responsibility for their deaths: \u201cWith Sarah all I wanted was her to shut up. And one day she did.\u201d<\/p>\n<p>For each child, doctors found possible, but not definitive, evidence for natural causes of death. Yet taken together, expert witnesses said, the deaths were suspicious, because multiple cases of sudden infant death syndrome (SIDS) within a single family are extremely rare\u2014let alone four of them. The New South Wales Supreme Court sentenced Folbigg to 40 years in prison, reduced to 30 years by a 2005 appeal. A 2019 inquiry upheld her conviction, and a 2021 appeal was dismissed.<\/p>\n<p>Critics say the case rested heavily on the reasoning popularized in the 1990s by British pediatrician Roy Meadow, who asserted that with respect to child deaths, \u201cone is a tragedy, two is suspicious, and three is murder unless there is proof to the contrary.\u201d Pediatrician Susan Beal cited a variation of \u201cMeadow\u2019s law\u201d during a 2003 hearing on what evidence could be admitted in Folbigg\u2019s trial.<\/p>\n<p>Meadow testified in court cases himself as well. But his reputation fell apart after the case of British solicitor Sally Clark, who in 1999 was convicted of murdering her two infant sons. Meadow testified that the chance of two SIDS deaths in a low-risk family like Clark\u2019s was one in 73 million. That calculation assumed SIDS could not have inherited risk factors, statistician Phil Dawid of the University of Cambridge wrote in a report for Clark\u2019s first appeal in 2000. He put the chance of the two deaths at a less outlandish one in 1 million, \u201cor even much higher,\u201d and pointed out that double infanticide is also vanishingly rare. The court should weigh both rare possibilities against each other, he says, along with all the other evidence.<\/p>\n<p>Clark lost the appeal, but she was exonerated at a second appeal in 2003, partly because it came to light that pathologist Alan Williams had failed to disclose evidence that one of the babies had <em>Staphylococcus aureus<\/em> in his spinal fluid, a possible natural cause of death. The appeal judges said Meadow\u2019s statistical evidence\u2014which could have had \u201ca major effect\u201d on the jury\u2014should not have been admitted.<\/p>\n<p>Williams was barred from working for the U.K. Home Office for 3 years and Meadow lost his medical license, a decision later overturned by the U.K. High Court. After the scandal, the attorney general ordered a review of 297 infanticide cases, and decided to drop charges in three cases and review the convictions in 28 others.<\/p>\n<p>There may be exculpatory medical evidence in Folbigg\u2019s case as well. In 2020, a group of researchers led by Peter Schwartz at the Italian Auxological Institute published a paper showing <a href=\"https:\/\/academic.oup.com\/europace\/article\/23\/3\/441\/5983835\" target=\"_blank\" rel=\"noopener\">Folbigg\u2019s two daughters both had a newly discovered genetic variant<\/a> that impairs cells\u2019 ability to regulate calcium, leading to a greatly increased risk of cardiac arrhythmia and sudden death. The paper led the Australian Academy of Science and Folbigg\u2019s lawyers to launch a petition in March 2021, signed by 90 scientists, <a href=\"https:\/\/www.science.org.au\/news-and-events\/news-and-media-releases\/statement-australian-academy-science-kathleen-folbigg\" target=\"_blank\" rel=\"noopener\">asking New South Wales Governor Margaret Beazley to pardon Folbigg<\/a>. Beazley ordered a new inquiry; hearings are due to begin in February.<\/p>\n<p>Clark, despite her vindication, never recovered and died of acute alcohol poisoning in 2007. Her family and the coroner\u2019s office attributed the death to severe distress from the \u201ccatastrophic experience.\u201d<\/p>\n<\/div>\n<\/div><\/div>\n<p><a href=\"https:\/\/www.science.org\/content\/article\/unlucky-numbers-fighting-murder-convictions-rest-shoddy-stats\" class=\"button purchase\" rel=\"nofollow noopener\" target=\"_blank\">Read More<\/a><br \/>\n Anthony Motsinger<\/p>\n","protected":false},"excerpt":{"rendered":"<p>A version of this story appeared in Science, Vol 379, Issue 6629.Download PDF LEIDEN, THE NETHERLANDS\u2014When a Dutch nurse named Lucia de Berk stood trial for serial murder in 2003, statistician Richard Gill was aware of the case. But he saw no reason to stick his nose into it. De Berk was a pediatric nurse<\/p>\n","protected":false},"author":1,"featured_media":599744,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[2403,2593,46],"tags":[],"class_list":{"0":"post-599743","1":"post","2":"type-post","3":"status-publish","4":"format-standard","5":"has-post-thumbnail","7":"category-fighting","8":"category-murder","9":"category-technology"},"aioseo_notices":[],"_links":{"self":[{"href":"https:\/\/newsycanuse.com\/index.php\/wp-json\/wp\/v2\/posts\/599743","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/newsycanuse.com\/index.php\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/newsycanuse.com\/index.php\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/newsycanuse.com\/index.php\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/newsycanuse.com\/index.php\/wp-json\/wp\/v2\/comments?post=599743"}],"version-history":[{"count":0,"href":"https:\/\/newsycanuse.com\/index.php\/wp-json\/wp\/v2\/posts\/599743\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/newsycanuse.com\/index.php\/wp-json\/wp\/v2\/media\/599744"}],"wp:attachment":[{"href":"https:\/\/newsycanuse.com\/index.php\/wp-json\/wp\/v2\/media?parent=599743"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/newsycanuse.com\/index.php\/wp-json\/wp\/v2\/categories?post=599743"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/newsycanuse.com\/index.php\/wp-json\/wp\/v2\/tags?post=599743"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}