Cell site analysis; testing understanding via internal consistency checks

This paper is aimed at Cell Site Analysis Expert Witnesses. Ground Truth Data (GTD) are essential to validation exercises, but in the UK access to practitioner-generated Call Data Records (the traces considered by Cell Site Analysis experts) are restricted, reducing opportunities for practitioners to test their understanding against real-world data. This paper outlines methods by which casework material might be used to potentially detect issues within understanding of uncertainties (and therefore improve the reliability of analyses) by reviewing the properties of casework material in parallel with the casework assessment being conducted. Four case examples are given in which assessments of the reliability of understanding of uncertainties are tested (two examples for assessing Call Data Record GPRS time uncertainties, one for reliability of survey results and one for assessing the reliability of "geo" data from Encrochat examinations). The methods proposed are intended to provide a deeper layer of Quality Assurance; they are not intended to replace validation using GTD.