The purpose of this article is to suggest the value of a research tool which has rarely been used in studies in instruction in writing: baseline measurement of group and individual performances. This approach was used in examining the results of a study of a self-instructional program in narrative writing which was prepared for and tested by secondary school students. During instruction, a process approach to writing, students were taught to use a set of questions to systematically and sequentially select a subject for a narrative, to develop a rough draft, and to make additions to expand the narrative. The goal of instruction was that students would achieve and/or maintain control of the structure of the narrative while learning to expand their narrative for the sake of completeness, development, and interest. An instrument was designed to measure three qualities indicative of control of structure and three characteristics of expansion. Of the 27 students who completed the program, the majority showed positive pretest-posttest changes in the variables related to expansion and demonstrated control of structure on both pretests and posttests. The baseline measures were found to be very useful. (JM)