Abstract: A method for determining credibility of content in a number of documents includes: obtaining topics from each document; for each document, generating topic combinations, each topic combination being a subset of the topics of the document; for each topic combination, obtaining a summary from the corresponding document; performing a semantic similarity test on each pair of two summaries that are respectively from two documents, so as to obtain a similarity percentage between the two summaries; for a group of the topic combinations that are identical combinations of topic(s), calculating a credibility score for the group based on the similarity percentage(s) calculated for the summaries that correspond to the topic combinations in the group.