Complexity, accuracy, and fluency as indices of college-level L2 writers’ proficiency

Several studies have explored complexity, accuracy, and fluency (CAF) as an index of language development, as an index of language performance, and as an index of writing quality. Although there have been studies that dealt with complexity measures as an index of proficiency, none so far have examined it in the company of accuracy and fluency as indices of proficiency. Thus, this study investigates whether CAF measures differentiate the four proficiency levels of L2 writers and whether relationships exist among the 18 CAF measures. More than 5000 essays from the International Corpus Network of Asian Learners of English (ICNALE) were analyzed using the L2 Syntactic Complexity Analyzer. Overall findings reveal that an interaction exists between language proficiency and CAF measures. Specifically, the length of production unit indices, degree of phrasal sophistication indices, weighted clause ratio, and words per text were found to best separate proficiency levels. The study also presents the patterns of relationship among the CAF measures which provided insights into how multiple measures may be selected and reclassified in so far as language proficiency is concerned. Implications for L2 writing assessment, pedagogy, use of automated text analyzers, and future studies are discussed.