National Board of Public Health Examiners (NBPHE) Certificate in Public Health (CPH): Evaluation of the inaugural examination

We describe the initial examination of the first core public health credentialing examination. In August 2008 close to 700 graduates of CEPH accredited schools or programs sat for the first national credentialing examination based upon core academic public health competencies. The examination was based upon core and cross-cutting academic competencies in public health, and was prepared with the assistance of the National Board of Medical Examiners. Questions were written by volunteers chosen to represent the broad range of public health knowledge, experience and background. Overall, the examination metrics were very favorable, particularly for a new examination. These included a 3% standard error of the measurement; a KR20 reliability estimate for the total examination, a measure of score consistency, of 0.91; and a mean discrimination index of 0.21 indicating that the test items adequately separated high- and low-scoring candidates. Post-examination validation measures led to the discard of 19 of the 200 multiple choice questions. Overall, examinees did somewhat better in environmental health; health administration and the cross-cutting competencies. The examinees that tended to score higher were those with SPH doctoral degrees; those with many years of practice; those for whom English was a primary language; those working at a state or national location; and those with concentrations in epidemiology. Further development of questions related to cross-cutting competencies is under way.