11. A computer program product for evaluating candidate answers to questions in a target knowledge domain, the computer program product including a computer readable medium, wherein the computer readable medium is not a signal, the computer program product comprising computer program instructions that, when executed, cause a computer to perform operations comprising: identifying, by a question answering module, a plurality of evidence items in the target knowledge domain; identifying, by the question answering module, a plurality of answers to questions in the target knowledge domain; determining, by the question answering module, associations between an evidence item and one or more of the answers forming an association based at least in part on a value associated with an evidence item supporting or contradicting an answer to a question; and assigning a correlation value for an association between a particular evidence item and a particular answer to a particular question, the correlation value indicating a strength with which the particular evidence item supports or contradicts the particular answer to the particular question; identifying, by the question answering module, an evidence item for which a value has not been received, and identifying, by the question answering module, a most valuable evidence item for which a value has not been received based at least in part on the most valuable evidence item having a highest correlation value of the associations between the plurality of evidence items and the answers to the questions; receiving, by the question answering module from a user, a question; receiving, by the question answering module, values for the one or more evidence items; and providing, by the question answering module, an answer to the question in dependence upon the associations between each evidence item and one or more of the answers and the values for the one or more evidence items.
11. A computer program product for evaluating candidate answers to questions in a target knowledge domain, the computer program product including a computer readable medium, wherein the computer readable medium is not a signal, the computer program product comprising computer program instructions that, when executed, cause a computer to perform operations comprising: identifying, by a question answering module, a plurality of evidence items in the target knowledge domain; identifying, by the question answering module, a plurality of answers to questions in the target knowledge domain; determining, by the question answering module, associations between an evidence item and one or more of the answers forming an association based at least in part on a value associated with an evidence item supporting or contradicting an answer to a question; and assigning a correlation value for an association between a particular evidence item and a particular answer to a particular question, the correlation value indicating a strength with which the particular evidence item supports or contradicts the particular answer to the particular question; identifying, by the question answering module, an evidence item for which a value has not been received, and identifying, by the question answering module, a most valuable evidence item for which a value has not been received based at least in part on the most valuable evidence item having a highest correlation value of the associations between the plurality of evidence items and the answers to the questions; receiving, by the question answering module from a user, a question; receiving, by the question answering module, values for the one or more evidence items; and providing, by the question answering module, an answer to the question in dependence upon the associations between each evidence item and one or more of the answers and the values for the one or more evidence items. 12. The computer program product of claim 11 further comprising computer program instructions that, when executed, cause the computer to perform an operation comprising processing, by the question answering module, one or more information sources associated with a target knowledge domain.