Investigating a customized generative AI chatbot for automated essay scoring in a disciplinary writing task

The release of ChatGPT in 2022 has greatly influenced research on language assessment. Recently, there has been a burgeoning trend of investigating whether Generative (Gen) AI tools can be used for automated essay scoring (AES); however, most of this research has focused on common academic genres or exam writing tasks. To respond to the call for further investigations in recent studies, our study investigated the relationship between writing scores from a GenAI tool and scores from English teachers at a university in Hong Kong. We built a Chatbot to imitate the exact procedures English teachers need to follow before marking student writing. The Chatbot was applied to score 254 technical progress reports produced by engineering students in a disciplinary English course. Then we conducted correlation tests to examine the relationships between the Chatbot and English teachers on their total scores and four analytical scores (i.e., task fulfillment, language, organization, and formatting). The findings show a positive and moderate correlation on the total score (r = 0.424). For the analytical scores, the correlations are different across the four analytical domains, with stronger correlations on language (r = 0.364) and organization (r = 0.316) and weaker correlations on task fulfillment (r = 0.275) and formatting (r = 0.186). The findings indicate that GenAI has limited capacity for automated assessment as a whole but also that a customized Chatbot has greater potential for assessing language and organization domains than task fulfillment and formatting domains. Implications are also provided for similar future research. © 2025 Elsevier Inc.