ATOM at CheckThat! 2025: Retrieve the Implicit - Scientific Evidence Retrieval

Abstract

With the rapid growth of scientific publications and their increasing circulation through social media, tracing claims back to their original sources has become increasingly difficult. The CheckThat! 2025 Claim Source Retrieval task addresses this challenge by requiring systems to retrieve the scientific paper implicitly referenced in a social media post. In this paper, we present our approach to solving this task. We explore a two-stage retrieval pipeline that combines lexical and dense retrievers with both pointwise and listwise re-rankers. We evaluate the impact of enriching document representations with full-text and summary content from CORD-19, and analyze trade-offs between model size, retrieval effectiveness, and runtime.