For decades, forensic science has carried a great deal of weight in the courtroom. Forensic evidence showing alleged matches in bullet marks, tire tracks, bite marks, shoeprints and fingerprints has been instrumental in many cases. Judges and juries often take this evidence at face value and convict accordingly. But how reliable is it?
According to a recent article in Science magazine, forensic evidence may not be nearly as reliable as everyone has been led to believe. In fact, the National Academy of Sciences (NAS) stated that "No forensic method has been rigorously shown to have the capacity to consistently, and with a high degree of certainty, demonstrate a connection between evidence and a specific individual or source."
Convicted And Then Exonerated By DNA Evidence
There have been many instances of people being convicted on the strength of things like bite mark comparisons, only to be exonerated later by DNA evidence. Even evidence that has long been held as infallible, like matching fingerprints, has now been shown to have a fairly significant error rate. This has led scientists to take a new approach to this evidence in terms of how it is reviewed and presented in court, a statistical approach.
The Center for Statistics and Applications in Forensic Evidence (CSAFE), a team of statisticians and legal professionals, has been tasked with creating databases, statistical models and other tools that would allow scientists to assess the likelihood that a piece of evidence, a shoeprint, for example, might have come from the defendant's actual shoe and not a similar shoe. This is a massive undertaking, considering all of the types and variations of shoes exist in the world. In the meantime, scientists are being more careful in the terminology they use in courtrooms to communicate about this evidence so as not to mislead judges and juries into believing certainty when there is not.
From a criminal defense standpoint, it is important for an attorney to be able to effectively cross-examine witnesses presenting forensic evidence in order to draw out the potential weaknesses for a judge and jury to understand. At Dawid & Gatti, PLLC, we recognize this evidence for what it is and attack it appropriately.