Abstract

The introduction of complex software into routine casework is not without challenge. A number of models are available to interpret complex mixtures. Some of these are commercial, whereas others are open source. For a comprehensive validation protocol see Haned et al Sci and Justice (206) 104-108). In practice, methods are divided into quantitative or qualitative models and there is no preferred method. A number of cases have been reported in the UK using different software. For example, in R v. Fazal, the prosecution and defence used different software to analyse the same case. Different likelihood ratios were obtained and both were reported to the court – a way forward to prevent confusion in court is presented. This paper also highlights the necessity of ‘equality of arms’ when software is used, illustrated by several other cases. Examples of problematic proposition formulations that may provide misleading results are described.