Designed to measure the effect of context on the ability of students to interpret structurally ambiguous sentences, this test consists of 20 items, ten of which are based on the surface structure ambiguities of the Sentence Interpretation Test (SIT). The criteria established for the construction of the Contextual Ambiguity Test (CAT) included item selection from the SIT, one sentence embedded in one paragraph to limit alternative interpretations, selection of vocabulary judged as grade 5 or below, paragraphs which stimulated naturally occurring reading situations, a consistent paragraph length of about sixty words, a strictly adhered to test format, and submission of the test to two groups of people. [This document is one of those reviewed in The Research Instruments Project (TRIP) monograph "Measures for Research and Evaluation in the English Language Arts" to be published by the Committee on Research of the National Council of Teachers of English in cooperation with the ERIC Clearinghouse on Reading and Communication Skills. A TRIP review which precedes the document lists its category (Reading), title, author, date, and age range (intermediate, junior high), and describes the instrument's purpose and physical characteristics.] (RB)