@inproceedings{valentino-etal-2021-natural,
    title = "Do Natural Language Explanations Represent Valid Logical Arguments? Verifying Entailment in Explainable {NLI} Gold Standards",
    author = "Valentino, Marco  and
      Pratt-Hartmann, Ian  and
      Freitas, Andr{\'e}",
    editor = "Zarrie{\ss}, Sina  and
      Bos, Johan  and
      van Noord, Rik  and
      Abzianidze, Lasha",
    booktitle = "Proceedings of the 14th International Conference on Computational Semantics (IWCS)",
    month = jun,
    year = "2021",
    address = "Groningen, The Netherlands (online)",
    publisher = "Association for Computational Linguistics",
    url = "https://preview.aclanthology.org/jlcl-multiple-ingestion/2021.iwcs-1.8/",
    pages = "76--86",
    abstract = "An emerging line of research in Explainable NLP is the creation of datasets enriched with human-annotated explanations and rationales, used to build and evaluate models with step-wise inference and explanation generation capabilities. While human-annotated explanations are used as ground-truth for the inference, there is a lack of systematic assessment of their consistency and rigour. In an attempt to provide a critical quality assessment of Explanation Gold Standards (XGSs) for NLI, we propose a systematic annotation methodology, named Explanation Entailment Verification (EEV), to quantify the logical validity of human-annotated explanations. The application of EEV on three mainstream datasets reveals the surprising conclusion that a majority of the explanations, while appearing coherent on the surface, represent logically invalid arguments, ranging from being incomplete to containing clearly identifiable logical errors. This conclusion confirms that the inferential properties of explanations are still poorly formalised and understood, and that additional work on this line of research is necessary to improve the way Explanation Gold Standards are constructed."
}