Content validity of the National Board Dental Hygiene Examination

This article describes a protocol that was employed to validate the content of the National Board Dental Hygiene Examination (NBDHE) using two separate practice analyses. The protocol consisted of the following phases: (1) the careful definition of the domain of knowledge and skills required for successful entry-level dental hygiene practice, (2) the conduct of a survey to gather information regarding the judgments of practicing dental hygienists on the important knowledge, abilities, and skills required of entry-level dental hygiene practice, (3) the analysis of the survey data, (4) the integration of the survey findings with the examination content using a two-dimensional matrix, (5) development of the updated specifications of the examination based on the practice analysis data, and (6) implementation of the updated specifications for subsequent item and test development. Survey data from 1,284 and 1,388 full-time practicing dental hygienists for the 2002 and 2009 practice analyses, respectively, were analyzed. A two-dimensional matrix was used to map the content of the examination to the practice of dental hygiene based on the practice analysis data. The mapping showed that the distribution of items in the content specifications reflected actual dental hygiene practice. Thus, the adequacy of the content validity of the NBDHE was confirmed.