7. The computer program product of claim 6 , wherein the query comprising an expertise, the confidence score is used to indicate a relative level of the expertise for each selected expert.
6. A computer program product for calculating confidence scores, the computer program product comprising a computer-readable storage medium having program code embodied therewith, wherein the computer readable storage medium is not a transitory signal per se, the program code executable by a processor to cause the processor to: execute, via the processor, a document-oriented search based on a query in an index of documents to generate a set of document results, each document in the set of document results is associated with at least one potential expert; analyze, via the processor, the document results to produce a list of potential experts; calculate, via the processor, an expertise score for each potential expert based on a calculated content score and metadata score for each potential expert and sorting the potential experts by the expertise scores; select, via the processor, a predetermined number of potential experts with higher expertise scores from the list of potential experts; calculate, via the processor, an evidence diversity score for each selected expert, wherein the evidence diversity score comprising a predetermined threshold number of different activities associated with the selected expert; calculate a confidence score for each potential expert based on diversity constrained content score and a diversity-constrained metadata score for each potential expert, wherein the diversity-constrained content score is calculated using the evidence diversity score and the content score for the potential expert, the diversity-constrained metadata score is calculated using the evidence diversity score and the metadata score the potential expert, the content score is calculated based on a number of different content document types and associations associate with the potential expert, the content document types and associations are gathered by parsing websites and stored in a data repository, the metadata score is calculated based on profile-related information associated with the potential expert, and the confidence score is further calculated based on a social score, wherein the processor is configured to generate a graph of connections between the predetermined number of selected experts, the social score for each selected expert is calculated using the graph and based on a number of connections to other selected experts; and send a list of experts with associated confidence scores that are above a confidence score threshold to a client device.