Correcting performance-rating errors in oral examinations

Although oral examinations are widely used for making decisions regarding an individual's level of competence, they are frequently of limited reliability. A significant part of the error in oral performance ratings is due to the tendency for some evaluators to be lenient and others to be stringent in their assignment of ratings. This article describes and evaluates a simple method to identify and correct for errors of leniency and stringency. The method, which is based on a regression model recommended by Wilson (1988), extends and simplifies the procedures recommended by Cason and Cason (1984, 1985). The method provides an estimate of each individual's performance that has been corrected for errors of leniency and stringency. In addition, it produces for each rater an index of leniency or stringency and several other statistics useful in evaluating the properties of rating data. The regression method is applied to performance ratings from three separate administrations of an oral examination in a medical specialty. The results indicate modest but significant levels of leniency and stringency error; correcting for such errors would change the pass/fail decisions for about 6% of the examinees. Limitations of the procedure, as well as the need for additional research, are discussed.