A Pilot Rasch Scaling of Lawyers’ Perceptions of Expert Bias

How seriously do attorneys consider the biases of their retained mental health experts? Participants in this pilot study included 40 attorneys, randomly selected from a pool of members of the Pennsylvania Bar Institute, who rated—for their biasing potential—several situations that might affect the behavior of an expert. A Rasch analysis produced a linear scale as to the perceived biasing potential of these different items from most to least biasing. Among other results, the study suggests that attorneys do view mental health experts who work on both sides of cases as being more balanced in their testimony. However, they also indicated that they have a preference for using individuals who repeatedly testify for one side. Working for only one side in both civil and criminal cases yielded large scaled values. Additional comments offered by respondents indicated that: (1) an opposing expert also serving as the litigant’s treater and (2) an opposing expert being viewed as a “hired gun ” (supplying an opinion only for money) were viewed by subjects as not being very biased. A discussion of the results raises the need for future research in this area. J Am Acad Psychiatry Law 34:482–91, 2006 The demand for psychiatric and psychological expert testimony has multiplied over the past three decades, in both criminal and civil cases, because of the in