The big headline for the past several days has been that an audio expert hired by The Orlando Sentinel, Thomas J. Owen, had concluded that the person screaming for help on the 911 tape when a neighbor called in was not George Zimmerman because voice biometric analysis of the scream could only find a 48% match, and a much higher match (I’ve seen reference to 60% and 90% in different reports) would be needed.
The analysis was done comparing the Zimmerman 911 phone call voice with the voice on the separate 911 call from the neighbor.
Like the original ABC video tape supposedly showing Zimmerman uninjured, Owen’s analysis has caused a firestorm of pontification that Zimmerman’s self-defense argument was a lie and that Zimmerman executed Martin.
Tom Maguire has done an exellent job running down the various uncertainties with this type of voice analysis, as has Jeralyn at Talk Left, a criminal defense attorney who has used Owen as an expert in the past. The point of their numerous posts is not that Owen is wrong, but that caution must be used given the nature of voice biometric analysis which is not universally accepted and which may be subject to challenge in court as not sufficiently reliable as to be admitted in evidence.
Equally important, as Tom points out again today, such analysis normally is done using numerous similar exemplars from the subject, so that a subject saying “help” could be compare to the person on the tape saying “help.” In this case so far, however, there were no such exemplars, as an exemplar of Zimmerman’s voice screaming help was not taken so as to be compared to the 911 recording.
More @ Legal Insurrection
No comments:
Post a Comment