1. A method of enhancing the accuracy of a question-answer system, said method comprising: identifying missing information from a corpus of data, said missing information comprising any information that improves a confidence for a candidate answer to a question, said identifying said missing information comprising: evaluating a piece of evidence and producing an evidence score according to a scoring process that reflects a degree to which said piece of evidence supports or refutes said candidate answer, classifying said piece of evidence as marginal evidence if said score is below a threshold value, and evaluating said marginal evidence to identify said missing information; generating a follow-on inquiry that prompts for said missing information to be provided; outputting said follow-on inquiry to an external source; receiving a response to said follow-on inquiry from said external source; and adding said response to said corpus of data.