Item responses from a standardized language arts usage and expression test were submitted to an ordering-theoretic data analysis procedure to identify the significant prerequisite relationships that underlay the data set. Responses were elicited from a sample of 81 sixth graders who took the Iowa Tests of Basic Skills, Form G, Level 12 usage and expression test, which contains 22 usage items and 18 expression items. The test assesses 28 skills objectives that fall into seven major categories (conciseness and clarity; appropriateness; organization; and use of verbs, pronouns, modifiers, and context). Ordering theory, which is defined as an approach to fundamental measurement that has as its intent the definition of the best fitting linear or non-linear hierarchical network among a series of tests, was the basis for the analysis. It is a deterministic measurement model that uses task response patterns to identify both linear and non-linear qualitative, prerequisite relations among tasks or behaviors. In general, it was found that success with paradigmatic elements was a prerequisite for success with syntagmatic units. The paper concludes with an illustration of the means by which ordering-theoretic results can be used in instructional design. Three figures and two data tables are included. (TJH)