Writing is a complex activity that requires transcription and self-regulation. We used multiple-group structural equation modeling to test the contribution of transcription (handwriting and spelling), planning, revision, and self-efficacy to writing quality at 2 developmental points (Grades 4-6 vs. 7-9). In Grades 4-6, the model explained 76% of the variance in writing quality, and transcription contributed directly to text generation. This finding suggests that, for younger students, handwriting and spelling were the strongest constraints to text generation. In Grades 7-9, the model explained 82% of the variance in writing quality. Although transcription did not contribute directly to text generation, it contributed indirectly through planning and self-efficacy. The progressive automatization of transcription throughout school years may contribute to the acquisition and development of self-regulatory skills, which, in turn, positively influence the quality of text generation. Explicit instruction and practice in handwriting, spelling, planning, and revising along with nurturing of realistic self-efficacy beliefs may facilitate writing development beyond primary years of schooling. (Contains 1 figure and 4 tables.)