Walidacja wewnętrzna programu biostatystycznego LRmix Studio

• Authors: Anna Brągoszewska , Michał Boroń

Title variants

EN

Internal validation of LRmix Studio biostatistical software

Abstracts

EN

The source of DNA in a stain is never known with full certainty despite the fact that the evidential profile may match a DNA profile of a given person from the population. The statistical methods, including the likelihood ratio (LR) allow estimating the evidential power of the obtained result and assessing the ratio of the odds between competing hypotheses as to the origin of a DNA profile or mixture. Therefore using analyses based on probabilistic methods seems to be logically justified and allows reducing the subjectivism of interpretation of results. Thorough knowledge and understanding of the principles of operation and limitations of the tools used for statistical interpretation of the results of biological traces analyses in forensics is the key stage that precedes the formulation of conclusions. The process of checking the efficiency of LRmix Studio software as well as reliability and repeatability of results involved single profiles and mixtures from two and three persons. 1971 comparisons with referential profiles were performed. The correctness of generated conditional probabilities was determined and the limits, i.e. drop-outs number in the evidential profile whose exceeding might bring about false LR values were identified.

PL

Źródło pochodzenia DNA w śladzie nigdy nie jest znane z całą pewnością, mimo iż profil dowodowy może być zgodny z profilem DNA danej osoby z populacji. Metody statystyczne, w tym iloraz wiarygodności, pozwalają oszacować siłę dowodową uzyskanego wyniku oraz ocenić stosunek szans między konkurencyjnymi hipotezami, dotyczącymi pochodzenia profilu lub mieszaniny DNA. W rezultacie stosowanie analiz opartych na metodach probabilistycznych wydaje się logicznie uzasadnione oraz pozwala zmiejszyć subiektywizm w interpretacji wyników badań. Dokładne poznanie i zrozumienie zasad działania oraz ograniczeń narzędzi wykorzystywanych do statystycznych interpretacji wyników badań śladów biologicznych w kryminalistyce jest kluczowym etapem poprzedzającym formułowanie wniosków płynących z tych analiz. Proces sprawdzenia wydajności programu LRmix Studio oraz wiarygodności i powtarzalności wyników obejmował pojedyncze profile oraz mieszaniny od dwóch i trzech osób. Wykonano 1971 porównań z profilami referencyjnymi. Określono poprawność generowanych prawdopodobieństw warunkowych oraz wyznaczono ograniczenia w postaci liczby zjawisk drop-out w profilu dowodowym, których przekroczenie może generować fałszywe wartości LR.

Keywords

PL

mieszaniny DNA; iloraz wiarygodności; LRmix Studio; walidacja; genetyka sądowa

EN

DNA mixtures; likelihood ratio; LRmix Studio; validation; forensic DNA analysis

• Publisher: Centralne Laboratorium Kryminalistyczne Policji
• Journal: Problemy Kryminalistyki
• Year: 2019
• Issue: 306
• Pages: 33-43

Dates

published

2019

Contributors

author

Anna Brągoszewska

• Centralne Laboratorium Kryminalistyczne Policji

author

Michał Boroń

• Centralne Laboratorium Kryminalistyczne Policji

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Identifiers

DOI

10.34836/pk.2019.306.4

Biblioteka Nauki

2065737