Levenshtein Distance as a Measure of Accuracy and Precision in Forensic PCR-MPS Methods

Accuracy and precision determinations are standard components of method validations where they help to describe the performance of methods. Despite their importance, a standard approach to calculating these parameters is not available for forensic PCR-MPS methods that detect sequence-based alleles. In this paper, we describe a method based on the Levenshtein distance metric which aptly summarizes method accuracy in terms of the closeness of read sequences to reference sequences, and method precision in terms of the agreement among read sequences. Inaccuracy or imprecision in forensic methods can lead to wrong allele calls. By expressing method performance in terms of a distance metric, this method places PCR-MPS on equal footing with distance-based measures in PCR-CE methods. Summary statistics based on the Levenshtein distance can be used to compare performance of different kits, markers, sequencers, or methods.