A clinically relevant model, grounded in nursing theory, has evolved to become a midrange theory. This article describes the processes used to derive, validate, revise, and test the Caregiving Effectiveness Model. Testing of this midrange theory used prospective longitudinal research with family members caring for patientsrequiring lifelong, complex, technology-based home care. It presents the conceptual critiques and statistical procedures and discusses derivation of model-generated nursing interventions and implications for use of these validation processes in developing nursing knowledge. The article summarizes limitations of the model and presents recommendations for future research.