If writing matters, how can we improve it? This study investigated the nature of writing plan quality and its relationship to the ensuing writing scores. Data were drawn from the 1998 Provincial Learning Assessment Programme (PLAP) in Writing, which was administered to pupils in Grades 4, 7, and 10 across British Columbia, Canada. Common features of writing quality were qualitatively identified in a sample of writing plans across the three grade levels. An analytic scoring scheme based on (1) identified features of writing quality in writing plans, (2) evaluative terms commonly used as criteria to measure writing performance in both large-scale and classroom assessments, and (3) theory and research in writing, was developed and used to assess a sample of 1,797 writing plans. Correlation and regression analyses were used to determine relationships between quality of writing plans and writing scores. Evidence of features of writing quality in writing plans was associated with higher writing scores. Identification of features of writing plan quality provides valuable instructional information to promote student writing. (Contains 10 tables and 8 figures.)