A method for calculating the importance of at least one of a plurality of electronic documents, based on (i) a plurality of electronic documents, (ii) information on referencing relation between each pair of the electronic documents, (iii) an important phrase, and (iv) a response coefficient determining phrase, (i) through (iv) being stored in a storage device, the method comprising:
- (a) calculating importance unique to one electronic document of a given electronic document among the plurality of electronic documents, on the basis of the degree of similarity between the important phrase and a phrase included in the given electronic document;
- (b) identifying at least one of other electronic documents which references the given electronic document, on the basis of the reference information;
- (c) calculating a response coefficient against the given electronic document, on the basis of at least one of the degrees of similarities between a phrase included in the other electronic documents and the response coefficient determining phrase;
- (d) calculating total importance of the given electronic document, on the basis of the importance unique to one electronic document of the given electronic document, the response coefficient, and total importance of the other electronic documents;
- and
- (e) calculating a total importance of each of the electronic documents in an electronic document group in which the given electronic document and the other electronic documents are directly and indirectly linked to each other on the basis of the reference information through relations of referencing and being referenced, by performing (a) through (d) on each pair of electronic documents having a mutual relation of directly referencing and being referenced in the electronic document group.