The specific way shoes are manufactured may directly influence the specific design and size characteristics of footwear and, therefore, can be of great importance in footwear examinations. The class characteristics of shoe outsoles are frequently shared by all other footwear from that manufacturer of that size and design. But in other instances, outsoles may possess variations which distinguish them from others, even within the same size and design. In some instances, the degree of variation in a particular manufacturing step may be limited; that is, the characteristics can and will repeat, but only a percentage of the time. In some less frequent methods, the variations of certain features can be so great that the shoes are unique before ever being worn. Knowledge of this and the ability to recognize these features is useful and can assist the examiner in both the identification and elimination of shoes. It also provides the examiner with a much greater understanding of class characteristics of shoes.