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.

多项研究探索了复杂性，准确性和流利性（CAF）作为语言发展的指标，语言性能的指标和写作质量的指标。尽管已经进行了将复杂性度量作为熟练度指标的研究，但到目前为止，还没有人将准确性和流利性作为熟练度指标进行检查。因此，本研究调查了CAF措施是否区分了L2写作者的四个熟练水平，以及18种CAF措施之间是否存在关系。使用L2句法复杂度分析器分析了来自国际英语亚洲语料库网络（ICNALE）的5000多篇论文。总体发现表明，语言能力和CAF措施之间存在相互作用。具体来说，生产单位索引的长度，短语熟练度指标的程度，加权从句比率和每篇文字的单词被认为是最好的独立水平。这项研究还提出了CAF措施之间的关系模式，从而就语言能力方面提供了有关如何选择和重新分类多个措施的见解。讨论了对L2写作评估，教学法，自动文本分析仪的使用和未来研究的影响。