Print Email Facebook Twitter A Quantitative Comparison of the Performance of Likelihood Ratio Systems in Trace-Reference Problems Title A Quantitative Comparison of the Performance of Likelihood Ratio Systems in Trace-Reference Problems Author Versteegh, Wouter (TU Delft Electrical Engineering, Mathematics and Computer Science) Contributor Fokkink, R.J. (mentor) Parolya, N. (graduation committee) Ypma, R.J.F. (graduation committee) Degree granting institution Delft University of Technology Programme Applied Mathematics Date 2024-05-08 Abstract In forensic science, the strength of evidence is calculated mainly by statistical models called likelihood ratio systems. In court cases, the specific-source likelihood ratio system is used by forensic scientists to determine if a trace originates from a known reference, called the trace-reference problem. However, collecting sufficient data to create a specific source model may be time-consuming and costly. If the number of court cases becomes too high this could be problematic. Therefore there is a need for other models that can perform as well as a specific-source model if it is infeasible.A common-source model could be a solution, as this model can be re-used over cases. To this end, we introduce two common-source systems: a common-source feature-based system and a common-source score-based system. We compare their performance to a specific-source score-based system in a trace-reference setting. The simulations show that the common source feature-based method is the best-performing likelihood ratio system if the dimensionality is not too high, and the sources are equally variable. The analysis shows that the common-source score-based method can work as effectively as a specific-source score-based model in certain scenarios. Additionally, we researched a preprocessor, known as percentile rank, which aims to consider typicality for score-based methods. For the common-source score-based system, using a percentile-rank preprocessor can improve the performance for large sample sizes, while considering the rarity of the measurements. Subject Likelihood ratio systemForensic statisticsCommon sourceSpecific source To reference this document use: http://resolver.tudelft.nl/uuid:6bc63bac-8200-459c-9681-521e6f43daa5 Part of collection Student theses Document type master thesis Rights © 2024 Wouter Versteegh Files PDF Master_Thesis_Wouter_Vers ... _Final.pdf 9.84 MB Close viewer /islandora/object/uuid:6bc63bac-8200-459c-9681-521e6f43daa5/datastream/OBJ/view