Determination of passing scores on certification examinations: an unresolved issue.

In the field of clinical laboratory science, certification may be obtained by passing the National Certification Agency for Medical Laboratory Personnel (NCA) examination. This multiple-choice test is competence-based and criterion-referenced, and uses a modified Angoff procedure to establish the passing score. For this study, the NCA examination scores of 1,868 certification applicants (mostly new graduates) and 111 selected laboratory practitioners were compared. Although the NCA examination is designed to define the level of minimum competence, the failure rate of practitioners identified by their supervisors as minimally competent was almost four times greater that that of the certification applicants. Even the most competent group of practitioners scored well below the applicants for certification. These findings suggest that the examination cut-off point may not really define minimal competence and that the method used to determine the passing score might not be appropriate for certification examinations.