PURPOSE. To evaluate the impact of the quality of nursing diagnoses, interventions, and outcomes in an acute care hospital following the implementation of an educational program. METHOD. In a pretest–posttest experimental design study, nurses from 12 wards of a Swiss hospital received an educational intervention—an introductory class and consecutive classes, using a case discussion method—to implement nursing diagnoses, interventions, and outcomes. Two sets of 36 randomly selected nursing records were evaluated before and after implementation. The quality of documented nursing diagnoses, interventions, and nursing-sensitive patient outcomes was assessed by 29 Likert-type items with a 0–4 scale instrument, called Quality of Nursing Diagnoses, Interventions, and Outcomes (Q-DIO) and tested using t -tests. FINDINGS. Significant enhancements in the quality of documented nursing diagnoses, interventions, and outcomes were found following the implementation of a planned educational program. CONCLUSIONS. The implementation of NANDA, NIC, and NOC (NNN) nursing diagnoses, interventions, and outcomes led to higher quality of nursing diagnosis documentation, etiology-specific nursing interventions, and nursing-sensitive patient outcomes. IMPLICATIONS FOR NURSING PRACTICE. Educational measures support nurses to improve documentation of diagnoses, interventions, and outcomes. The Q-DIO is a useful audit tool. [ABSTRACT FROM AUTHOR]