What Does My QA Model Know? Devising Controlled Probes Using Expert Knowledge

Kyle Richardson, Ashish Sabharwal


Abstract
Open-domain question answering (QA) involves many knowledge and reasoning challenges, but are successful QA models actually learning such knowledge when trained on benchmark QA tasks? We investigate this via several new diagnostic tasks probing whether multiple-choice QA models know definitions and taxonomic reasoning—two skills widespread in existing benchmarks and fundamental to more complex reasoning. We introduce a methodology for automatically building probe datasets from expert knowledge sources, allowing for systematic control and a comprehensive evaluation. We include ways to carefully control for artifacts that may arise during this process. Our evaluation confirms that transformer-based multiple-choice QA models are already predisposed to recognize certain types of structural linguistic knowledge. However, it also reveals a more nuanced picture: their performance notably degrades even with a slight increase in the number of “hops” in the underlying taxonomic hierarchy, and with more challenging distractor candidates. Further, existing models are far from perfect when assessed at the level of clusters of semantically connected probes, such as all hypernym questions about a single concept.
Anthology ID:
2020.tacl-1.37
Volume:
Transactions of the Association for Computational Linguistics, Volume 8
Month:
Year:
2020
Address:
Cambridge, MA
Editors:
Mark Johnson, Brian Roark, Ani Nenkova
Venue:
TACL
SIG:
Publisher:
MIT Press
Note:
Pages:
572–588
Language:
URL:
https://aclanthology.org/2020.tacl-1.37
DOI:
10.1162/tacl_a_00331
Bibkey:
Cite (ACL):
Kyle Richardson and Ashish Sabharwal. 2020. What Does My QA Model Know? Devising Controlled Probes Using Expert Knowledge. Transactions of the Association for Computational Linguistics, 8:572–588.
Cite (Informal):
What Does My QA Model Know? Devising Controlled Probes Using Expert Knowledge (Richardson & Sabharwal, TACL 2020)
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PDF:
https://aclanthology.org/2020.tacl-1.37.pdf