Span-Based Fact Verification Task

A Span-Based Fact Verification Task is a fact verification task that is an evidence-based NLP task requiring evidence span extraction from a corpus to classify claims as supported, refuted, or unverifiable.

• AKA: Evidence-Based Fact Checking Task, Span-Grounded Claim Verification.
• Context:
  • It can typically require Evidence Retrieval before verdict assignment.
  • It can typically demand Span-Level Precision for evidence identification.
  • It can typically enforce Evidence Completeness for valid verdicts.
  • It can typically support Claim Decomposition for complex verification.
  • It can typically enable Verdict Explanation through evidence presentation.
  • ...
  • It can often involve Multi-Document Evidence for comprehensive verification.
  • It can often require Stance Detection from evidence spans.
  • It can often incorporate Temporal Reasoning for time-sensitive claims.
  • It can often handle Contradictory Evidence across sources.
  • ...
  • It can range from being a Single-Hop Verification Task to being a Multi-Hop Verification Task, depending on its reasoning complexity.
  • It can range from being a Binary Verification Task to being a Three-Way Verification Task, depending on its verdict options.
  • ...
  • It can process Factual Claims with evidence corpus.
  • It can output Verification Verdicts with supporting spans.
  • It can be solved by a Span-Based Fact Verification System.
  • It can be evaluated by a Fact Verification Performance Measure.
  • ...
• Example(s):
  • FEVER Task verifying claims against Wikipedia.
  • SciFact Task checking scientific claims with paper evidence.
  • MultiFC Task verifying multi-domain claims.
  • TabFact Task verifying against tabular evidence.
  • Climate-FEVER Task for climate-related claims.
  • ...
• Counter-Example(s):
  • Opinion Classification Tasks, which assess subjectivity not factuality.
  • Sentiment Analysis Tasks, which determine attitude not truth.
  • Binary Classification Tasks without evidence requirement.
• See: Fact Checking Task, Evidence-Based Classification, Claim Verification Task, Misinformation Detection.

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