Group trends and individual variability in writing development: a descriptive grammatical complexity analysis

Abstract This study aims to examine group trends and individual variability of descriptive Grammatical Complexity (GC) in writing development. A longitudinal sample of 41 high school EFL learners is followed for an academic year (12 waves of data collection), resulting in a corpus of 492 texts, coded for eight descriptive GC features of academic writing. Our analysis reveals different sets of descriptive GC features relevant to capturing group trends and individual variability in writing development. At the group level, two phrasal-level GC features could capture significant changes in group means over time; at the individual level, four types of clausal and phrasal GC features showed significant associations between individual variability over time (measured by Standard Deviation of differences) and gains (as measured by the increase of usage frequency). Findings are discussed with regard to modeling both inter-individual and intra-individual trajectories in writing development and pedagogical implications attuned to both group and individual needs.