  We propose a framework for discriminative Information Retrieval (IR) atop
linguistic features, trained to improve the recall of tasks such as answer
candidate passage retrieval, the initial step in text-based Question Answering
(QA). We formalize this as an instance of linear feature-based IR (Metzler and
Croft, 2007), illustrating how a variety of knowledge discovery tasks are
captured under this approach, leading to a 44% improvement in recall for
candidate triage for QA.
