Questioning the Validity of Forensic DNA Match Statistic
News Nov 10, 2015
DNA mixtures of two or more people are common. When DNA evidence connects a defendant to a crime, courts require a match statistic. Jurors rely on this match strength to help decide guilt. But the reliability of some match statistics has been questioned.
The Combined Probability of Inclusion (CPI) is a popular match statistic for DNA mixtures. For 15 years, crime laboratories have generated CPI statistics on hundreds of thousands of mixtures. However, a new study shows that CPI behaves more like a random number generator than like a reliable measure of human identification.
The research article “Inclusion probability for DNA mixtures is a subjective one-sided match statistic unrelated to identification information” was published recently. The paper explains why CPI always gives the same “one in a million” answer, instead of providing accurate match information.
“How DNA mixtures are interpreted affects criminal justice and public safety,” says author Dr. Mark Perlin of Cybergenetics. “The inclusion method compares a mixture with a suspect, relying on CPI for statistical support. But if CPI does not accurately convey identification information, its patina of science lends no meaningful support.”
The FBI’s free PopStats software includes a CPI calculator. However, a 2005 NIST study showed 69 crime laboratories reporting a wide range of inaccurate statistics (from ten thousand to hundred trillion, or just “inconclusive”) on the same mixture sample. The FBI has never developmentally validated its CPI software.
The current CPI controversy has shuttered the Washington, DC crime lab, and sparked reconsideration of 24 thousand cases in Texas. Conviction integrity may require re-examination of past CPI mixture cases. Previously reported inculpatory statistics can be irrelevant or unreliable, while an inconclusive result can mask exculpatory evidence.
Cybergenetics develops patented TrueAllele technology that objectively interprets DNA evidence. Seven published peer-reviewed studies havevalidated TrueAllele’s reliability. The system has examined mixture evidence from most states, overcoming admissibility challenges in seven. The company provides computer systems and databases to crime labs, and expert witness services. Cybergenetics offers free TrueAllele screening for calculating accurate match statistics from DNA mixtures.
Neural Computer Hears Like HumansNews
Modelling the human senses is an incredibly complex task. Our brains arrange cells into complex hierarchies that process information from our surroundings. Now, a group at MIT have created a model of the human auditory cortex that can hear sounds and music in the same way that humans do.READ MORE
Deceased Data: Should Your Online Remains Be Treated Like Physical Remains?News
In 2018, your death doesn't just leave behind a body. It leaves behind a huge online footprint - your digital remains. A new study asks whether these remains should be treated and respected as a corpse would, and whether museums may provide a blueprint for the preservation process.READ MORE
Comments | 0 ADD COMMENT
International Conference on Analytical and Bio Analytical Techniques
Oct 31 - Nov 01, 2018
16th Annual Conference on Laboratory Medicine and Pathology
Sep 17 - Sep 18, 2018