Automatic Text Evaluation through the Lens of Wasserstein Barycenters

Pierre Colombo, Guillaume Staerman, Chloé Clavel, Pablo Piantanida


Abstract
A new metric BaryScore to evaluate text generation based on deep contextualized embeddings (e.g., BERT, Roberta, ELMo) is introduced. This metric is motivated by a new framework relying on optimal transport tools, i.e., Wasserstein distance and barycenter. By modelling the layer output of deep contextualized embeddings as a probability distribution rather than by a vector embedding; this framework provides a natural way to aggregate the different outputs through the Wasserstein space topology. In addition, it provides theoretical grounds to our metric and offers an alternative to available solutions (e.g., MoverScore and BertScore). Numerical evaluation is performed on four different tasks: machine translation, summarization, data2text generation and image captioning. Our results show that BaryScore outperforms other BERT based metrics and exhibits more consistent behaviour in particular for text summarization.
Anthology ID:
2021.emnlp-main.817
Volume:
Proceedings of the 2021 Conference on Empirical Methods in Natural Language Processing
Month:
November
Year:
2021
Address:
Online and Punta Cana, Dominican Republic
Editors:
Marie-Francine Moens, Xuanjing Huang, Lucia Specia, Scott Wen-tau Yih
Venue:
EMNLP
SIG:
Publisher:
Association for Computational Linguistics
Note:
Pages:
10450–10466
Language:
URL:
https://aclanthology.org/2021.emnlp-main.817
DOI:
10.18653/v1/2021.emnlp-main.817
Bibkey:
Cite (ACL):
Pierre Colombo, Guillaume Staerman, Chloé Clavel, and Pablo Piantanida. 2021. Automatic Text Evaluation through the Lens of Wasserstein Barycenters. In Proceedings of the 2021 Conference on Empirical Methods in Natural Language Processing, pages 10450–10466, Online and Punta Cana, Dominican Republic. Association for Computational Linguistics.
Cite (Informal):
Automatic Text Evaluation through the Lens of Wasserstein Barycenters (Colombo et al., EMNLP 2021)
Copy Citation:
PDF:
https://aclanthology.org/2021.emnlp-main.817.pdf
Video:
 https://aclanthology.org/2021.emnlp-main.817.mp4
Code
 additional community code
Data
MS COCOWMT 2016