Background: Writing is an essential literacy skill; however, public school students often receive inadequate writing instruction, particularly as they move into middle and high school. However, research has shown that the nature of writing tasks assigned can impact writing development and student achievement measured by standardized assessments. With the need to assess teacher efficacy, districts are increasingly using some form of value-added modeling, although researchers warn of relying solely on value-added scores to distinguish between more and less effective teachers. Purpose: This study investigated the intellectual challenge of typical writing tasks and the intellectual quality of student work in classrooms of higher and lower value-added middle school English language arts teachers to understand what value-added modeling might capture in terms of writing instruction. In particular, this article investigates how higher and lower value-added teachers differ in terms of (1) the intellectual challenge of typical tasks assigned, (2) the quality of supports surrounding the tasks, and (3) the quality of student work produced. Research Design: Data for this study were collected as part of a larger study that identified pairs of middle school ELA teachers within the same school who were in their third through fifth years of teaching. Within each school, we identified at least one teacher in the fourth (top) quartile and one in the second (lower) quartile based on their measures of value-added to student achievement. We analyzed the typical and challenging writing tasks and corresponding student work for the intellectual quality, looking within and across the two groups of teachers to document patterns of instructional practices. Conclusions: We found differences in the consistency of challenge and scaffolds between the two groups, with higher value-added teachers more consistently providing challenging and supportive tasks. Teachers whose typical writing tasks maintain a high degree of challenge are associated with higher student performance, as defined by a measure of teacher value-added. This implies the importance of educating teachers regarding the importance and nature of challenging assignments.