We have to understand the limitations of DNA testing, says Rose
Toronto criminal lawyer David Rose tells Law Times that a new scientific report which cast doubt on the efficacy of DNA testing could throw old cases into doubt.
“The thing about science is that you only find out after the fact that the thing you’ve been doing for years is not as good as you thought it was,” says Rose, a partner with Neuberger Rose LLP.
The 2011 report, published by Itiel Dror of University College London and Greg Hampikian of Boise State University in Idaho, describes an experiment in which 17 North American DNA examiners interpreted data from a criminal case, with no contextual information. The analysts reportedly produced inconsistent interpretations, with the authors noting that the cause of these varied results was the difference in contextual information given to examiners.
Rose tells Law Times that the authors came up with two interesting observations. “Firstly, if every examiner is not going to come up with the same result, there is subjectivity,” he says.
“Secondly, extraneous information can affect an expert’s result,” he adds.
Analysts, says Rose, routinely receive background information from a submission document sent with the sample.
“DNA testing might be the gold standard for clean, single, uncorrupted samples when compared with a clean, uncorrupted sample from a database. Even in relation to complex cases, DNA testing is still far superior to every other kind of testing, but we have to understand that there are limitations,” he says.
Rose says he hopes the scientific community will react positively, accept the empirical evidence before them, and accept the limitations of their ability.
“My personal opinion is that there should be a peer review program to find out how often an analyst’s results vary from the findings of their peers. Every scientist should be subject to some form of double-blind testing to find out what their accuracy rate is,” he adds. Read Law Times Story