In summary, it may be noted that these three systems have been developed separately but can be linked, provisionally (Daly, 1993). Outcomes are linked to the problem (nursing diagnosis) in a diagnostic statement. Interventions are linked to the related or contributing factors. Diagnosis-intervention linkages (McCloskey and Bulechek, 1996) assume that a nursing diagnosis is being used as a contributing factor for another nursing diagnosis and that the classification is similar to a dictionary of terms. Linkages are more easily seen when diagnosis, intervention, and outcomes are identified within one project, such as the Home Health Care Classification (Saba, 1992) which shares many concepts with the NANDA Taxonomy or the Omaha Classificafion System (Martin and Sheet, 1992) for community health, which also overlaps considerably with the NANDA

Similar difficulties have been encountered by the three groups of classifiers. These were

1. concept development: definition of elements, level of abstraction, issues of validity and reliability, and
2. classification: determining the key constructs for organization of a nursing taxonomy and decisions about classification of elements that are autonomous, collaborative, or both.

In the 25 years since the national effort began in a volunteer organization to systematically classify nursing diagnoses, and later interventions and outcomes, great progress has been made. Perhaps now, the time nurses spend on documenting the care they give can result in documentation that is systematically organized to advance nursing knowledge, develop nursing practice, and improve patient care.