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A Diagnosis of the Primary Difference between EuroForMix and STRmix™

NCJ Number
Journal of Forensic Sciences Volume: 69 Issue: 1 Dated: 2024 Pages: 40-51
Date Published
12 pages

This article reports on research that discusses the comparison in output from two probabilistic genotyping softwares, EuroForMix and STRmix™, highlighting that the main differences between the two occur between log(10)LR 4 and -4, and notes that understanding differences in the software is important for proper interpretation of results.


There is interest in comparing the output, principally the likelihood ratio, from the two probabilistic genotyping softwares, EuroForMix (EFM) and STRmix™. Many of these comparison studies are descriptive and make little or no effort to diagnose the cause of difference. There are fundamental differences between EFM and STRmix™ that are causative of the largest set of likelihood ratio differences. This set of differences is for false donors where there are many instances of LRs just above or below one for EFM that give much lower LRs in STRmix™. This is caused by the separate estimation of parameters such as allele height variance and mixture proportion using MLE under H(p) and H(a) for EFM. This can result in very different estimations of these parameters under H(p) and H(a). It results in a departure from calibration for EFM in the region of LRs just above and below one. (Published Abstract Provided)

Date Published: January 1, 2024