Forensic metrology: its importance and evolution

Measurements play a fundamental role in nowadays forensic activities, especially in criminal justice. Guilt or innocence and the severity of a sentence do often depend upon the results of measurements. On the other hand, it is well-known that measurement results are always affected by uncertainty, so that any decision based on measurement results carries an implicit risk of being wrong: uncertainty helps in estimating this risk. If this concept is translated into the juridical world, it is quite immediate to recognize that uncertainty may quantify how reasonable is the doubt with which a verdict is rendered by the trier of facts. Unfortunately, forensic disciplines are still largely unaware of the basic, fundamental concepts of metrology. This paper is aimed at showing how forensic metrology is developing in different countries and reporting a few cases where metrology played a key role.