From a social policy and economic perspective, one taxonomy is inconsistent with the shift toward devolution of power and increasing autonomy to individual states. For example, certain funds are released to states in the form of block grants. Medicaid, the joint federal and state program aimed at providing health care coverage to the poor, provides shared reimbursement from federal and state governments, the largest proportion of which comes from state sources. In turn, many of the Medicaid regulations are established and implemented at the state level, within certain federal guidelines and limited federal oversight. This variability in funding and decision-making at the state level suggests that there will be variability in health care needs, resource allocation, health care service delivery, and monitoring mechanisms, including data collection, across states. Hence, variability across states and geographic areas necessitates variability of data elements that will be collected across states and regions.

Simultaneously, within health care, responsibility and accountability for decision-making is increasingly decentralized to the clinician closest to the point of care delivery — and, ultimately, and/or to the extent possible, to the individual patient or family. This effort should, in theory, improve the quality of service delivered to the consumer, increase autonomy and job satisfaction for the provider, and decrease negative aspects of the practice environment. In both policy and management, however, the trend toward increasing autonomy, whether to states or individuals, can shift easily back toward a more centralized mode of decision-making whenever dramatic changes occur within political or management authority. These possible shifts necessitate that data are captured in a manner that allows integration across levels and sites of care delivery, providers, and realms of management and control.

The term taxonomy refers to a hierarchical system. As defined in Table 1, taxonomy comprises vocabulary and terms; in turn, vocabulary is made up of terms, or names at the most basic level. This hierarchical system is similar to that of a theoretical system, whereby theories comprise constructs, constructs consist of concepts, and so forth. An important assumption of these two systems is that there are relationships between the levels. While discussions of taxonomy within the context of informatics is not typically linked to theory, the analogy of the two systems is particularly relevant to this discussion, given that useful taxonomies are linked to significant theory (Benzon at http://www.newsavanna.com/wlb/CE/Arena/Arena07/shtml; retrieved 1998, document no longer available online).

This paper proposes a model that demonstrates where multiple vocabularies, classifications, and taxonomies may be needed, and where they need to converge to fewer taxonomies, and finally at what level a unicode or unified taxonomy might be required if global (international, worldwide, or universal) comparisons are to be made of nursing care.