Accuracy and reproducibility of conclusions by forensic bloodstain pattern analysts. (August 2021)

• Record Type: Journal Article
• Authors: Hicklin, R. Austin; Winer, Kevin R.; Kish, Paul E.; Parks, Connie L.; Chapman, William; Dunagan, Kensley; Richetelli, Nicole; Epstein, Eric G.; Ausdemore, Madeline A.; Busey, Thomas A.
• Is Part Of: Forensic science international. Volume 325(2021)
• Publication Date: 2021-08
• Subjects: Bloodstain pattern analysis -- Forensic science -- Forensic identification; Medical jurisprudence -- Periodicals; Chemistry, Forensic -- Periodicals; Forensic Medicine -- Periodicals; Médecine légale -- Périodiques; Chimie légale -- Périodiques; Gerechtelijke geneeskunde; Gerechtelijke chemie; Gerechtelijke psychiatrie; Chemistry, Forensic; Medical jurisprudence; Electronic journals; Periodicals; Electronic journals; 614.1
• DOI: 10.1016/j.forsciint.2021.110856
• Languages: English
• ISSNs: 0379-0738

Abstract

Highlights: Conclusions by bloodstain pattern analysts were often erroneous and often contradicted other analysts. On samples with known causes, 11.2% of responses were erroneous. Both semantic differences and contradictory interpretations contributed to errors and disagreements. Abstract: Although the analysis of bloodstain pattern evidence left at crime scenes relies on the expert opinions of bloodstain pattern analysts, the accuracy and reproducibility of these conclusions have never been rigorously evaluated at a large scale. We investigated conclusions made by 75 practicing bloodstain pattern analysts on 192 bloodstain patterns selected to be broadly representative of operational casework, resulting in 33, 005 responses to prompts and 1760 short text responses. Our results show that conclusions were often erroneous and often contradicted other analysts. On samples with known causes, 11.2% of responses were erroneous. The results show limited reproducibility of conclusions: 7.8% of responses contradicted other analysts. The disagreements with respect to the meaning and usage of BPA terminology and classifications suggest a need for improved standards. Both semantic differences and contradictory interpretations contributed to errors and disagreements, which could have serious implications if they occurred in casework.