Bloodstain classification methods: What methods do analysts use, why, and how accurate are they?

Many bloodstain pattern classification methods exist in the literature that analysts could use in casework. Currently, no research demonstrates which classification methods bloodstain pattern analysts use or why they use those specific methods; therefore, this study aims to address this gap and support the development of a standardised classification approach. This research surveyed 79 participants working in Bloodstain Pattern Analysis (BPA) to determine which classification methods are used and why. The most used classification methods were the ‘Passive, Spatter, and Altered,’ ‘other methods’ (such as OSAC BPA terminology and Passive, Spatter, Transfer), and ‘Taxonomic methodology,’ and that job role and court system influenced the method chosen. Participants also used their classification methods to classify ten bloodstain patterns. The average percentage of correct classifications was 85 %, consistent with previous research. The percentage of correct classifications was then compared to the classification methods used. No single classification method was shown to be more accurate than any other method for this specific sample. However, as assessing the accuracy and effectiveness of the classification methods was not the main aim of this study, further work is needed to conduct a thorough assessment that will aid in developing a standardised procedure.