Educators often observe differences in students' writing productivity, with some students stopping early while others continue to write for the given time. This study demonstrates how planning and goal setting are related to these written production patterns. A Growth Mixture Model identified three groups of writers: the "Early Terminators" who stopped writing early, the "Decelerating Producers" who continued to write for the 15 minutes though at a slowing rate over time, and the "Steady Writers" who wrote at a constant rate across the task. Students who had an additional year of instruction and who created more structured plans to use as a writing goal were more likely to continue writing across the task, pointing to the importance of strong instruction in planning and goal setting for upper elementary writing. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://bibliotheek.ehb.be:2222/en-US/products/dissertations/individuals.shtml.]