Specialty nursing certification programs, such as that administered by the American Board for Occupational Health Nurses, Inc. (ABOHN), must be firmly based on current practice to maintain validity. To determine this, ABOHN performed its most recent job analysis and role delineation study between 1992 and 1994. A comprehensive survey tool was developed by ABOHN Board members, and administered to all 3,805 certified occupational health nurses in practice at the time of the study. With a final return rate of 42.7%, the results were believed to be representative of the knowledge, skills, and abilities needed to practice occupational health nursing in the United States at the proficient level of practice. The results of the study formed the basis for the ABOHN test blueprints and the creation of two credentials for occupational health nurses: the Certified Occupational Health Nurse (COHN) and the Certified Occupational Health Nurse Specialist (COHN-S).