6. The method of claim 1 , wherein presenting the no-answer response to the user comprises presenting additional information to differentiate various causes for having no answer.
1. A method, in a computing system, for interpreting and distinguishing a lack of an answer to an input question, the method comprising: receiving an input question from a user; generating one or more hypotheses based on a corpus of source information; injecting a no-answer response into the one or more hypotheses to form a plurality of candidate answers, wherein the no-answer response is a candidate answer variant representing an absence of an answer; generating a plurality of features that support the plurality of candidate answers; performing evidence scoring and confidence scoring on each of the plurality of candidate answers based on the plurality of features to generate a confidence score for each of the plurality of candidate answers including the no-answer response; ranking the plurality of candidate answers, including the no-answer response, based on the evidence scoring and the confidence scoring to form a candidate answer ranking; and responsive to determining the no-answer response has a highest rank in the candidate answer ranking, presenting the no-answer response to the user.