The purpose of this study was to document the effects of applying the platform unity concept, a concept based on the principle of curriculum alignment. This principle states that the planned, the delivered, and the tested curricula are congruent. Specifically, platform unity aligns planned, domain-referenced content with appropriate test types. Mathematical formulae were created to determine numerically if planned and tested content were congruent. In addition, four other constructs were examined. They included overtesting and undertesting of course content and, effectiveness and efficiency of test item type selection. / Ph. D.