Look away now CSI fans: why forensics is not science and why that should concern you
Updated: Oct 4, 2019
In July of 2018 in Victoria, Joby Rowe was convicted of shaking to death his three month old daughter Alanah. Alanah had no external injuries, such as broken bones, bruising, or neck injuries. No witness saw Rowe shake Alanah. There was no history of abuse or violence. The evidence against Rowe was based purely on expert testimony from forensic “scientists” that Alanah had injuries that can only occur through being violently shaken.
Controversy over Shaken Baby Syndrome has raged in courtrooms throughout the world for decades. There have been hundreds of convictions, many for murder. Wanting answers, the Swedish commissioned an independent review of its scientific evidence base. Published in 2017, the review concluded that there is insufficient scientific evidence for the assertion that particular brain injuries provide proof that an infant was shaken. Indeed, the experts in the Joby Rowe case conceded that such an assertion does not have a ‘sufficient scientifically robust evidence base’.
If there is no scientific basis, why did two highly qualified forensic doctors provide testimony that Alanah’s injuries could only arise through shaking?
To answer this question, one needs to understand the difference between forensics and science. Most fields of forensic analysis were devised and developed by police working in the field, and involved little or no scientific method. The career of blood splatter expert Tom Bevel is illustrative. Having no scientific background, Bevel’s knowledge of blood splatter evidence was gained on the job, working for the Oklahoma City Police. Bevel then contracted out his services as a blood-spatter expert, primarily testifying for the prosecution. He taught courses and published a textbook as the field evolved, and spread. Courts throughout the world accepted the methods. A major review of forensic science in the U.S. in 2009 found that the opinions of blood-spatter experts are ‘more subjective than scientific’.
Forensic analysis of hair fibers, shoe prints, arson and bite marks have similar histories6,. Within a controlled scientific setting, forensic dentists could not even agree on whether a bite mark was human, let alone use it to identify a particular individual.7
The use of certain brain injuries as evidence that a baby was shaken has a similar history, but it was developed by medical doctors rather than police or dentists. Trying to understand what was happening when babies presented with brain injuries such as subdural hemorrhages, retinal hemorrhages, and cerebral edema, neurologist Norman Guthkelch proposed, in 1971, that this ‘triad’ of injuries may be caused by the brain being thrown about inside the skull. Guthkelch stated in 2012 that these were ‘simply hypotheses, not proven medical or scientific facts’. But by that time the medical community had embraced the hypotheses, and used this triad of injuries as evidence of child abuse. Just as police trained others in unscientific methods of blood splatter analysis, the ‘knowledge’ that this triad of brain injuries could only be caused by shaking was passed between medical practitioners. The hypothesis gained ‘acceptance and enormously widespread popularity, with no real investigation or even question as to its scientific validity’.
The controversy that has raged over Shaken Baby Syndrome is often portrayed as unsettled science. It is, rather, a dispute between scientists and well-meaning medical doctors who have an unsubstantiated belief that has been passed on, one to the other. The problem for Joby Rowe is that the beliefs of highly credentialed pathologists hold great sway over a jury, regardless that those beliefs have no basis in science.
Different fields of forensic analysis have taken various levels of action to incorporate scientific methods into their fields, to become more scientific. Yet our legal system has not changed the way it engages science, meaning that unscientific evidence continues to be presented under the banner of forensics.
 Australian Associated Press, Father, 26, denies killing his three- month-old daughter - but her injuries 'are a smoking gun for shaken baby syndrome', Daily Mail, 18 July 2018
 E.g. Tuerkheimer, D. Flawed Convictions: "Shaken Baby Syndrome" and the Inertia of Injustice
Oxford University Press, 2014
 Lynøe N, Elinder G, Hallberg B, Roseen M, Sundgren P, Eriksson A. Insufficient evidence for ‘shaken baby syndrome’ – a systematic review. Acta Paediatr 2017; 106: 1021–7
 Wells J, Pathologist testifies in child homicide trial, Bendigo Advertiser, March 22 2017
 Bevel, T. Bloodstain Pattern Analysis with an Introduction to Crime Scene Reconstruction, CRC Press 2008
 Committee on Identifying the Needs of the Forensic Sciences Community, National Research Council, Strengthening Forensic Science in the United States: A Path Forward National Research Council 2009
 President’s Council of Advisors on Science and Technology. Forensic science in criminal courts: ensuring scientific validity of feature-comparison methods. Washington, DC: Executive Office of the President of the United States
 Guthkelch AN. Infantile Subdural haematoma and its relationship to whiplash injuries Br Med J 1971; 2: 430.
 Uscinski, R. Shaken Baby Syndrome: An oddesey 2006 Neurol 46, Med. Chir. 57, 58