A construct, “A Theory of Nursing Care of Patients Who Have Had Spinal Anesthesia with Regard to the Need for Catheterization,” illustrates how a theory for practice discipline, as proposed by Dickoff et al. (1968), may be developed through four levels In the construct, as the theory develops step by step- I) factor-isolating or naming, 2) factor-relating or situation-depicting, 3) situation-relating-a) predictive or b) promoting or inhibiting, 4) situation- producing or prescriptive — based on data collected in practice, direction is provided for the prescription of activity aimed at reaching the goal of the theory.