Explain the critical difference between individual and class characteristics in evidence analysis, providing a specific example of each.

The critical difference between individual and class characteristics lies in their ability to uniquely identify a source. Class characteristics are features shared by a general group or category of items, while individual characteristics are unique features that distinguish one particular item from all others within that group or category. For example, the make and model of a shoe found at a crime scene are class characteristics; numerous shoes share these attributes. However, a unique wear pattern or a specific cut on the sole of that shoe are individual characteristics. Class characteristics can narrow down the potential sources, but they cannot pinpoint a single, unique origin. Individual characteristics, when matched between evidence and a known source, can establish a unique association, meaning the evidence originated from that specific source to the exclusion of all others. Identifying both class and individual characteristics is crucial in forensic investigations. Class characteristics help narrow the field of possible sources, while individual characteristics provide the strongest level of identification.