Evaluation of an electronic comparison system and implementation of a quantitative effectiveness criterion.

The identification of fired bullets and spent cartridge cases is one of the key tasks of forensic science. The traditional comparison of signatures on specimen with a large collection with only a microscope is a very tedious and time-consuming work. Fortunately, electronic systems for performing a pre-selection have been invented since the last 25 years. On the basis of an expansive database the electronic comparison system used by the BKA, Germany, is evaluated and a mathematical value is proposed to rate the correlation quality. This effectiveness criterion can be valuable to give an objective assessment of different electronic comparison systems. Additionally, the applicability of the system on different calibres and land engraved area (LEA) width is discussed. The so called scores are also on disposition and their benefit to a decision-making is debated.