The Impact of ChatGPT-Based Learning Support on English Essay Writing Skills Among Undergraduate Students at the University of Nairobi, Kenya

Writing skills are essential in higher education as they enable students to communicate ideas clearly and succeed academically. However, many undergraduates struggle with clarity, coherence, and creativity in their writing. This study examined the effect of ChatGPT-based learning support on English essay writing among 341 first-year Bachelor of Education students at the University of Nairobi. Guided by social constructivist learning theory and Cognitive Load Theory, a quasi-experimental one-group pre-test/post-test design was used. Students completed standardized writing tests before and after a one-month period of ChatGPT-assisted learning integrated into classroom instruction. Data were collected through tests, questionnaires, and observations, then analysed using descriptive and inferential statistics. ANOVA results confirmed significant improvement, F(1,307) = 69.14, p < .001. Students who perceived ChatGPT as beneficial showed the largest improvements (19.87 to 25.21) compared to those with neutral perceptions (20.19 to 23.91) and those who did not consider it supportive (20.67 to 22.13). The strongest effects were linked to personalized feedback, grammar support, constant availability, and structured guidance. Observations and qualitative data indicated higher motivation, engagement, and self-correction. Despite concerns about factual reliability, students applied fact-checking and evaluation strategies. The study concludes that ChatGPT is an effective supplementary tool for improving ESL academic writing and recommends its integration within pedagogical frameworks that foster critical thinking and verification.