Inherent Biases in Reference-based Evaluation for Grammatical Error Correction

Leshem Choshen, Omri Abend


Abstract
The prevalent use of too few references for evaluating text-to-text generation is known to bias estimates of their quality (henceforth, low coverage bias or LCB). This paper shows that overcoming LCB in Grammatical Error Correction (GEC) evaluation cannot be attained by re-scaling or by increasing the number of references in any feasible range, contrary to previous suggestions. This is due to the long-tailed distribution of valid corrections for a sentence. Concretely, we show that LCB incentivizes GEC systems to avoid correcting even when they can generate a valid correction. Consequently, existing systems obtain comparable or superior performance compared to humans, by making few but targeted changes to the input. Similar effects on Text Simplification further support our claims.
Anthology ID:
P18-1059
Volume:
Proceedings of the 56th Annual Meeting of the Association for Computational Linguistics (Volume 1: Long Papers)
Month:
July
Year:
2018
Address:
Melbourne, Australia
Editors:
Iryna Gurevych, Yusuke Miyao
Venue:
ACL
SIG:
Publisher:
Association for Computational Linguistics
Note:
Pages:
632–642
Language:
URL:
https://aclanthology.org/P18-1059
DOI:
10.18653/v1/P18-1059
Bibkey:
Cite (ACL):
Leshem Choshen and Omri Abend. 2018. Inherent Biases in Reference-based Evaluation for Grammatical Error Correction. In Proceedings of the 56th Annual Meeting of the Association for Computational Linguistics (Volume 1: Long Papers), pages 632–642, Melbourne, Australia. Association for Computational Linguistics.
Cite (Informal):
Inherent Biases in Reference-based Evaluation for Grammatical Error Correction (Choshen & Abend, ACL 2018)
Copy Citation:
PDF:
https://aclanthology.org/P18-1059.pdf
Note:
 P18-1059.Notes.pdf
Poster:
 P18-1059.Poster.pdf
Code
 borgr/IBGEC