The purpose of this study was to develop a test that could be used both to diagnose student writing needs and to evaluate the effects of classroom teaching on the abilities of secondary school-junior college students to write expositorily. Data analysis was organized to indicate the extent to which a carefully designed objective test could validly measure expository writing abilities. Four expository abilities were selected by a jury of experts as being of highest significance to the expository process of communication--the abilities to define and stick to a purpose, to create transitions, to achieve variety by rearranging the elements of sentence patterns, and to recognize and write for a specific audience. Items designed to measure these four abilities were constructed in two forms, each of which included 40 multiple choice questions. The two forms were then given to 100 junior college students, after each had written an expository essay to serve as a criterion of his expository writing abilities. Scores on the criterion expository essay, graded according to a scale based on these four expository abilities, were then correlated with scores on the multiple choice tests. Results indicated that a carefully designed objective test can validly measure a student's ability to write in certain expository areas. (Author/JB)