COMPLETE DATASET: The Effects of Freezing Temperature on Bloodstain Impact Angles

This study's aim was to determine whether or not variability of bloodstain impact angles was codependent on temperature fluctuation. This involved a direct comparison of both ambient room temperature, and freezing temperature datasets, utilizing a novel deposition method whereby 0.05ml of human blood was dropped onto paper in accordance with predetermined impact angles (15°, 30°, 45°, 60°, 75°) under three temperature conditions (22.2 °C, 0 °C, and ‑6.1 °C). Impact angles were estimated using the length‑to‑width ratios of stains and Balthazard’s formula via the 2‑D ellipse tool in Cloud Compare’s ELipser app. A one‑way ANOVA showed remarkable differences among temperature groups at all angles (15°: p = 0.049; 30°: p = 0.049; 45°: p = 0.013; 60°: p < 0.001; 75°: p = 0.029). One‑sample t‑tests indicate that calculated angles generally underestimate true angles, with colder temperatures improving accuracy for steeper angles (≥45°) and warmer conditions performing better at shallower angles (15°–30°). This study explored the efficacy of bloodstain pattern analysis within the scope of below zero-degree Celsius conditions, and discovered variable accuracy.