Our premise is that from the perspective of maximum flexibility of data usage by computer-based record (CPR) systems, existing nursing classification systems are necessary, but not sufficient, for representing important aspects of “what nurses do.” In particular, we have focused our attention on those classification systems that represent nurses' clinical activities through the abstraction of activities into categories of nursing interventions. In this theoretical paper, we argue that taxonomic, combinatorial vocabularies capable of coding atomic-level nursing activities are required to effectively capture in a reproducible and reversible manner the clinical decisions and actions of nurses, and that, without such vocabularies and associated grammars, potentially important clinical process data is lost during the encoding process. The article discusses how the Nursing Intervention Lexicon and Taxonomy (NILT) is being used to describe patterns of care for patients receiving home care nursing. These patterns of care include intensity (frequency of interventions), focus of care (NILT category or categories with the highest percentage of interventions), and comprehensiveness of care (number of NILT intervention categories reflected). Thus with a means for quantifying care in holistic ways, nurses can now ask important questions about clinical care and its outcomes using empirical nursing data about care (i.e., categorized nursing intervention statements). Understanding how these data are expressed using nurses' natural language terms, and being able to categorize these interventions reliably, represent essential preliminary work for describing and defining data for inclusion in the automated record.