Assignment #2

Assignment #2 Paper Student’s Name Affiliation Course Number: Course Name Instructor’s Name Due Date Discuss the challenges that are faced when examining firearm, tire impressions, and hair evidence. Direct evidence collected by forensic scientists from firearms is always unique. This is because firearms examination mostly relies heavily on subjective visual comparison of bullet and cartridge marks. The challenges often arise when it comes to reliability and validity. It is clear that no two guns have the same lands and grooves, or even the serial number, but most of the evidence relies on the forensic expert’s opinion. Critics note that validation studies for ballistics lack broad scientific rigor, i.e., examiners regard themselves as specialists and practitioners of forensic techniques; nonetheless, they lack the training of research scientists in design, statistics, and scientific methodologies (Monson et al., 2022). Forensic experts suffer from methodological flaws in internal and external validity. An aspect of inconsistency is also experienced due to varying opinions and techniques. Environmental factors such as overheating or modifications to firearms can further complicate comparisons. Regarding tire tracks, it is often challenging when it comes to identifying which tire is specific to which track. Class characteristics, such as tread pattern and size, rather than unique identifiers, make definitive identification of a single tire almost impossible (Richetelli et al., 2024). Interpreting a specific tire is challenging, especially if there are other distorting factors like mud, snow, or uneven ground, and to some extent, degraded by weather or multiple overlapping tracks, making collection and interpretation challenging. This complicates interpretation and renders it difficult to correlate with a prospective vehicle (Richetelli et al., 2024). This reflects the problem that many tire patterns are mass-produced and do not vary uniquely between tires. When it comes to interpretation, it is necessary to recognize a tread pattern and distinctive features in the tire's tread and track. The examiner must then locate the tire that possesses those qualities; an exact match is required. This becomes challenging to verify with absolute certainty, especially when environmental conditions, wear and tear on the tire, or incomplete impressions obscure the distinctive markings that could link a track to a specific tire. Microscopic hair comparison can indicate that a hair is “consistent” with a subject, but it cannot uniquely identify an individual. To even reach this conclusion, each series of hair must be individually packaged, sealed, and labelled, presenting a significant task. According to the U.S. Department of Justice (2023), if hair comes into contact with fluids like blood, mixes with foreign materials such as tissue or other body fluids, it is best to keep it dry and place it in a separate collecting bag, such as an envelope. In light of such errors, the reliability of traditional hair comparison is considered poor by today’s standards. Contamination and loss of hair evidence (e.g., when no root is available for DNA) also further limit its utility. Discuss a minimum of two ways in which each of the challenges discussed above can be minimized or overcome. When it comes to firearm evidence, two key approaches can improve reliability and validity regarding the methods used in evidence assessment. The first one is to adopt an objective technology that can reduce examiner bias. This has been witnessed in 3D imaging techniques and automated matching algorithms which have been designed to quantify bullet and toolmark similarity (Hofmann et al, 2022). These tools also provide statistical measures of match quality, rather than relying solely on the visual inspection of the so-called "experts". Second, implementing blind proficiency testing embeds unbiased assessment into routine casework (Dorfman & Valliant, 2022). Studies also recommend “test-blind” programs so examiners do not know which cases are controls, which yields more accurate error estimates (Dorfman & Valliant, 2022). Enhanced training and standardized protocols (e.g., NIJ or NIST guidelines) can also align examiners on best practi...