"Who Are We Talking About?" Tracking the Referent in a Question Answering Series

The capability of handling anaphora is becoming a key feature for Question Answering systems, as it can play a crucial role at different stages of the QA loop. At the question processing stage, on which this paper is focused, it enhances the treatment of follow-up questions, allowing for a more natural interaction with the user. As much as the QA task evolves towards a realistic dialogue-based scenario, one of the concrete problems raised by follow-up questions is tracking their actual referent. Each question may in fact refer to the topic of the session, to an answer given to an earlier question, or to a new entity it introduces in the dialogue. Focusing on the referent traceability problem, we present and experiment with a possible data-driven solution which exploits simple features of the input question and its surrounding context (the target of the session, and the previous questions) to inform the next phases of the QA process.