1. A computer implemented method for managing credibility of a set of search results for a search query in a question answering system, the method comprising: determining, by a natural language processing technique configured to analyze at least a portion of the set of search results and at least a portion of the search query, at least one credibility factor configured to indicate similarity to a subject matter of the search query; establishing a relevance relationship between the at least one credibility factor and source information of a first search result of the set of search results, wherein the source information is based on the at least one credibility factor; and computing a credibility score for the first search result of the set of search results based on the relevance relationship between the at least one credibility factor and the source information of the set of search results.