The National Board Dental Hygiene Examination program is a part of the process for licensing dental hygienists. The examination assesses theoretical and applied knowledge in the basic biomedical, dental, and dental hygiene sciences, as well as community health. Standards for licensure examinations recommend that test publishers demonstrate a relationship between examination content and actual practice. METHOD: To this end, a validity study was conducted, which involved the definition of the domain of entry-level dental hygiene practice using 56 competencies; the conduct of a practice analysis survey designed to rate the importance of these competencies; and the linking of competencies to content elements in accordance with the competencies' importance ratings. Of the 3941 surveys distributed, 1841 participants responded and, of these, 1284 were full-time practitioners. The importance ratings for the competencies were translated into numbers of items. The number of items devoted to each competency was distributed across all applicable elements of the existing content specifications based upon the knowledge needed to support the realization of the competency. RESULTS AND DISCUSSION: The findings confirmed the adequacy of the content specifications in effect prior to 2005. However, based on this validity study, 2 sub areas of relatively little significance were eliminated, and 2 new areas were introduced. Specifically, Clinical Testing under Assessing Patient Characteristics (one item) and Professional Methods of Administering Fluorides under Using Preventive Agents (one item) were eliminated, and Dental Hygiene Treatment Strategies was incorporated with 4 items, and Professional Responsibilities was added with a total of 28 items. [ABSTRACT FROM AUTHOR]