Problems such as these raise the challenge that even if an international classification is desirable, it may not be feasible. Such a view is, however, unduly pessimistic.

One cause for optimism is the integration of a Unified Nursing Language System (UNLS) within the Unified Medical Language System (UMLS) which is being developed by the National Library of Medicine (Lindberg, Humphreys & McCray, 1993). The UMLS includes concepts, terms, strings and semantic relationships which enables terms from different vocabularies to be mapped from one language to another. The UMLS already includes the ANA recognized languages, the UK Read terms (which include nursing terms), and the vocabularies used in some non-English speaking countries.

The most important step, however — a pre-requisite for the successful international use of any standardized language or classification — would be the international adoption of an agreed nursing minimum data set. Until countries agree on the data elements to be described, the availability of standardized terminology and classification is irrelevant. It is 10 years since Werley and Lang (1988) identified as essential the four nursing elements of nursing diagnosis, nursing interventions, nursing outcomes and nursing intensity. Goosen (1998) has recently reviewed the minimum data sets developed in several countries. Nurses in most countries record nursing interventions in some form, but the concept of nursing diagnoses is not widely used in Europe and the only "problems" which nurses record are usually medical diagnoses. The recording of outcomes is rare in all countries, and although some system of predicting nursing workload is common, there is no agreed measure for nursing intensity.

Criteria for an International Classification

The ICNP project set criteria for its own classification as follows:

1. Broad enough to serve the multiple purposes required by different countries.
2. Single enough to be seen by the ordinary practitioner of nursing as a meaningful description of practice and a useful means of structuring practice.
3. Consistent with clearly defined conceptual frameworks but not dependent upon a particular theoretical framework or model of nursing.
4. Based on a central core to which additions can be made through a continuing process of development and refinement.
5. Sensitive to cultural variability.
6. Reflective of the common value system of nursing across the world as expressed in the ICN Code for Nurses.
7. Usable in a complementary or integrated way with the family of disease and health related classifications developed within WHO.

These criteria describe the challenge for any classification for nursing practice. They are not easy to meet, and success will not be quick. The ICNP has been described as "the kind of project that never ends but for which the need is urgent." It is certainly a goal worth aiming for.