Forensic Metrology: Uncertainty of Measurements in Forensic Analysis

In many cases, forensic scientists rely on measurements as a basis for their opinions. In the past, forensic scientists, testifying about such measurements, have often presented the court with a single point value. The problem is that there is an unavoidable and an inherent element of uncertainty in every measurement. The metrology has developed several methods of quantifying a measurement’s margin of error or uncertainty. By using these methods, the testifying expert can put the trier in a much better position to determine the appropriate evidentiary weight of the measurement. The purpose of this paper is to describe the problem of uncertainty in forensic science and in particular uncertainty in measurements by forensic scientists. In this paper, the problem of uncertainty is described in a relatively non-technical way. In other words, the discussion will focus on concepts rather than on analytical analysis.