NIST urges caution in use of likelihood ratio

The National Institute of Standards and Technology (NIST) released an article last week calling into question the use of the likelihood ratio to present evidence in court. NIST states that there is uncertainty about the appropriate use of the likelihood ratio. An expert’s subjective opinion may affect the calculation of the likelihood ratio, potentially distorting the evidence. More information is available here.

Attorneys who see a likelihood ratio in a lab report should consider the NIST report and  investigate further prior to trial. Many labs are moving toward implementation of the likelihood ratio for interpretation of DNA analysis. To my knowledge, the NC State Crime Laboratory and the Charlotte-Mecklenburg Police Department do not employ the likelihood ratio in their interpretations of DNA evidence, though it could be adopted at some point in the future. The likelihood ratio is used by some private laboratories, such as NMS Laboratories.