What distinguishes class characteristics from individual characteristics in forensic evidence?

Class characteristics are features that can be associated with a particular group or class of objects but not with a specific source. These characteristics help in establishing the general category to which a piece of evidence belongs. For example, the tread pattern on a shoe can indicate the brand and model, thus associating it with a group of shoes produced by that manufacturer. However, it doesn't point to any specific shoe that left the print.

In contrast, individual characteristics are unique to a particular item and can be traced back to a single source. These might include unique imperfections on a tool or the specific patterns of wear and tear on an object, which can tie it conclusively to a specific individual item.

Understanding the difference between these types of characteristics is crucial in forensic analysis. Class characteristics help narrow down possibilities, while individual characteristics can provide definitive links to suspects or pieces of evidence.