A study was conducted to examine the associations among the processes, skills, and content of the writing of children aged 9 through 14 years. A further objective was to explore the impact of developmetal changes by comparing the performance of children at the 9-10, 11-12, and 13-14 year age-levels. Subjects were 340 average students and 268 students with learning difficulties. Three writing tasks were designed to evaluate written output under increasingly demanding requirements for processing, memory, and organization: timed alphabet production, timed sentence memory items, and timed paragraph writing task. Each child's performance was rated for speed, motor fluency, quality of symbol production, and spatial organization. The results revealed significant differences between normal achievers and the learning difficulty group on virtually all writing measures. In particular, the children with learning difficulties showed significantly more problems on each of the nine processing measures of writing efficiency, including motor fluency, symbol production, and spatial orientation. They also wrote shorter paragraphs, used grammatically simpler sentences, and displayed a higher prevalence of semantic and syntactic confusions. The results suggest that children with learning difficulties struggle not only with the complex language and cognitive components of written output, but also with the basic prerequisites for writing efficiency that have already been acquired by their peer group. (HTH)