A study examined the effects of coauthoring, also referred to as collaborative writing, on student learning. Subjects were 24 students in a ninth-grade English class. Data were collected over the first 9-week quarter of the year. Eight collaborative writing triads were formed with a primary criteria in establishing heterogeneous groups in gender, race, and verbal ability/leadership. Students wrote three essays together, with three class sessions allowed to complete each essay. Argumentative topics were used. The third writing assignment was used for the study. A Likert-type questionnaire was completed by students after the last coauthoring experience and two interviews were conducted, one after the study and the other 7 months later, to ask what students remembered from coauthoring. Results indicated that students collaborating spent a greater percentage (39%) of their energies on planning and revising than solo authors do. Findings suggest that what students most remembered from collaborative writing was planning. Over 60% said they spent more time planning when coauthoring than when writing alone. Further, the 7-month interview findings revealed that 73% of students most remembered planning or brainstorming as something they learned. Although students did not seem to be aware of it, the revision process was also going on during what they recognized as "planning." (Contains 20 references and an appendix with coauthoring coding and procedural information.) (CR)