Beware of bad evidence
The capacity of bad science to subvert justice has too often been made plain in Ontario. Six years ago, an inquiry into the tragic failures of pathologist Charles Smith sought to expose the threat posed to our justice system by junk science and to provide the tools to guard against it. And yet the problem persists.
Last year, a series of Star investigations revealed scandalous shortcomings of the Motherisk hair-testing program at Sick Kids Hospital, casting doubt on thousands of child-protection rulings. And now, as Betsy Powell reported in Monday’s Star, an accused drunk-driver has been acquitted in Brampton after a forensic expert testified that the breathalyzer used by Ontario police produces faulty evidence.
It’s a ruling that could have vast implications — thousands of impaired driving charges are laid every year in Ontario. At the very least, it demands public reassurance from the ministry of the attorney general about the science and how it’s managed.
Toxicologist Ben Joseph told the court that during his time as a government scientist he became increasingly skeptical of the reliability of the Intoxilyzer 8000C, the breathalyzer used by Ontario police. In particular, Joseph suggested that the machine deteriorates with age, making it difficult to register accurate readings. More damning still, this brand of breathalyzer provides no “uncertainty of measurement,” an error rate essential to understanding the tool’s accuracy.
The upshot, according to the defence: convicting anyone based on a reading from this breathalyzer would be “flirting with disaster.” Ontario Court Justice Elinore Ready agreed. (The Crown has already filed an appeal.)
Joseph compared the case to those overturned in the wake of the Motherisk scandal. “It’s no different . . . no uncertainty of measurement here, no proper maintenance.” It is precisely this failure to recognize the uncertainty built into the tool’s measurements that, if true, is most troubling about Joseph’s testimony. That the breathalyzer test is imperfect should not be surprising. Rather, what should worry us is that our justice system seems to have once again failed to treat science and technology with due skepticism — if so, demonstrating the very hubris that allowed for Motherisk’s ascendancy and other similar perversions of justice.
Whether or not Justice Ready’s decision is upheld on appeal, whether or not the breathalyzer is as flawed as Joseph claims, the concerns raised in this case require internal reckoning in the attorney general’s office and a public response. Uncertainty is baked into science; it is the job of our public institutions, as science and technology become ever more entwined in their work, to learn how to manage these, to assess how much uncertainty exists, how much is tolerable, how best to reduce it and to be transparent in the process.
As defence lawyer Daniel Brown wrote in these pages last year: “Scientific evidence will continue to play an important role in our justice system, but we must continually remind ourselves of its potential pitfalls,” lest it be used to exonerate the guilty or convict the innocent.
That is the essential lesson of this ruling. Science is an imperfect, human project; our justice system should treat it as such. If we can’t have certainty in science, we must at least have clarity in law. Public safety and justice depend upon it.
Accused drunk driver’s acquittal casts doubt on reliability of breathalyzer tests