Evaluating Transformer Model Family Representations Through Automated Essay Scoring

Akchay Ozten, Rodrigo Wilkens


Abstract
Large Language Models have become central to Automated Essay Scoring (AES), typically through fine-tuned transformer encoders or prompt-based applications of decoder models. However, the representational capacity of decoder models as frozen embedding extractors remains largely unexplored. In this paper, we present a controlled comparison between encoder and decoder transformer embeddings for prompt-agnostic AES. Using regression models, we evaluate frozen representations across two English datasets. We analyzed scaling effects and the impact of integrating explicit linguistic features in hybrid configurations. Our results show that decoder embeddings consistently outperform encoder embeddings in embedding-only settings, with gains generalizing across holistic essay scoring and proficiency prediction. Scaling effects are modest, and hybrid models that combine contextual embeddings with linguistic features yield further improvements. Notably, frozen decoder embeddings achieve performance competitive with a fine-tuned BERT. These findings highlight the importance of representation-level properties in essay scoring.
Anthology ID:
2026.readi-1.11
Volume:
Proceedings of the Joint Workshop on Readability and Text Simplification (READIxTSAR) @ LREC 2026
Month:
May
Year:
2026
Address:
Palma, Mallorca (Spain)
Editors:
Matthew Shardlow, Thomas François, Raquel Amaro, Jorge Baptista, Rémi Cardon, Eugénio Ribeiro, Horacio Saggion, Regina Stodden, Amalia Todirascu, Rodrigo Wilkens
Venues:
READI | TSAR | WS
SIG:
Publisher:
ELRA Language Resources Association (ELRA)
Note:
Pages:
142–150
Language:
External URL:
https://lrec.elra.info/lrec2026-ws-readixtsar-11
DOI:
10.63317/35ytj3qcrwv4
Bibkey:
Cite (ACL):
Akchay Ozten and Rodrigo Wilkens. 2026. Evaluating Transformer Model Family Representations Through Automated Essay Scoring. In Proceedings of the Joint Workshop on Readability and Text Simplification (READIxTSAR) @ LREC 2026, pages 142–150, Palma, Mallorca (Spain). ELRA Language Resources Association (ELRA).
Cite (Informal):
Evaluating Transformer Model Family Representations Through Automated Essay Scoring (Ozten & Wilkens, READI-TSAR 2026)
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