Admissibility of Expert Testimony Based on the Grisso and Gudjonsson Scales in Disputed Confession Cases

While Grisso's scales for the measurement of competency to waive Miranda rights were originally developed in the late 1970s and early 1980s, they were published for commercial use in 1998. Similarly, the Gudjonsson scale for the measurement of interrogative suggestibility was developed in the late 1970s and early 1980s, but published for commercial use in 1997. Since that time, psychologists have sought to use these scales as the basis for expert testimony in cases involving a defendant's competency to waive Miranda rights, and in cases involving a defendant's confession in which the defense is based on the argument that the defendant was suggestible and therefore may have given a false confession. Such cases are beginning to be reported, as the use of the scales becomes more common, and as they are challenged under Daubert or Frye standards of admissibility. This article looks at the emerging case law in this area.