Is Unvalidated Science Undermining the Justice System? One Canadian Lawyer Says ‘Yes’


Improper science is an ‘alarming thread’ that runs through more than twenty Canadian wrongful convictions, heightening the need for better scientific training of judges and more information for juries, according to criminal defense lawyer and Toronto Director with the Criminal Lawyers’ Association Daniel Brown.

“Unlike in television shows, where an investigation and conviction is neatly wrapped up in 60 minutes, forensic evidence is often incomplete and open to interpretation,” Brown warns in an op-ed published today in the

Toronto Star


“Wealthy defendants are able to afford top lawyers and expert witnesses, but indigent accused or those from marginalized communities frequently bear the brunt of bad science evidence,” he continues, adding that the poor “cannot match cases assembled by well-funded police and prosecutors, sometimes pleading guilty to obtain a reduced sentence in the face of superficially overwhelming evidence.”

In the nearly two dozen Canadian wrongful murder conviction cases exposed in recent years by the

Association in Defence of the Wrongly Convicted (AIDWYC)

, unvalidated or improper science has already manifested itself in a number of ways, says Brown, ranging from “clothing fibers mistakenly believed to match one another; experts who incorrectly concluded that dog bites on a dead child were knife wounds inflicted by her mother; inept autopsies that misinterpreted the cause of death; biology samples contaminated by a government lab technician; and hair samples that anchored a murder conviction, yet later turned out to be worthless.”


Innocence Project

has long noted that many forensic techniques — such as hair microscopy, bite mark comparisons, firearm tool mark analysis and shoe print comparisons — have not been subjected to sufficient scientific evaluation and have resulted in error.  

Innocence Project client

Steven Mark Chaney

is just one recent example.  With the consent of the Dallas District Attorney, his murder conviction was recently vacated in large part because of testimony of two forensic dentists who wrongly claimed that his teeth matched to a mark on the victim’s body. Chaney spent 28 years in prison before he was released in October.

“It is all too easy to latch onto cutting edge science as being a final, perfect answer to our questions. However, the steady evolution in testing techniques ought to serve as a red flag,” adds Brown. “Judges must be better trained to weed out junk science and unwarranted opinions offered by experts. And they must warn juries about the perils of placing too much reliance on science or picking sides in a battle of experts.”

For its part, the Innocence Project has long advocated for reforms to prevent wrongful convictions based on unvaliated or improper forensic disciplines. Among its recommendations are the establishment of a national effort led by federal science agencies to identify research needs, establish priorities, and design criteria for reviewing forensic disciplines and the creation of state oversight commissions or advisory boards.

“Scientific evidence will continue to play an important role in our justice system,” concludes Brown, “but we must continually remind ourselves of its potential pitfalls.”

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