Exploring the ability of LLMs to classify written proficiency levels

This paper tests the ability of LLMs to classify language proficiency ratings of texts written by learners of English and Mandarin, taking a benchmarking research design approach. First, the impact of five variables (LLM model, prompt version, prompt language, grading scale, and temperature) on rating accuracy are tested using a basic instruction-only prompt. Second, the consistency of results is tested. Third, the top performing consistent conditions emerging from the first and second tests are used to test the impact of adding examples and/or proficiency guidelines and the use of zero-, one-, and few-shot chain-of-thought prompting techniques on accuracy rating. While performance does not meet levels necessary for real-world use cases, the results can inform ongoing development of LLMs and prompting techniques to improve accuracy. This paper highlights recent research on prompt engineering outside of the field of linguistics and selects prompt variables and techniques that are theoretically relevant to proficiency rating. Finally, it discusses key takeaways from these tests that can inform future development and why approaches that have been effective in other contexts were not as effective for proficiency rating.