This article demonstrates how theoretical substruction with its various levels of abstraction can be used as a guide for theory testing research. The article describes a method for substructing research hypotheses as well as an entire study. Substruction and its benefits, including assuring the internal consistency of model testing, are discussed as applied to a study testing hypotheses derived from proposition two of Orem's self-care deficit theory of nursing. This approach to theory testing is congruent with the coherence theory of truth and promises to contribute to the advancement of nursing epistemology.