1. A computer system for expanding attribute within attribute profiles to increase the strength of association between a query attribute and a set of attribute profiles associated with query-attribute-positive individuals, comprising: a) a memory containing attribute profiles for a set of individuals; b) a receiver for receiving a query attribute; c) a computer readable medium containing instructions, which when executed by a processor, result in the execution of the steps of: i) identifying a set of query-attribute-positive profiles; ii) identifying a set of query-attribute-negative profiles; iii) generating a set of attribute combinations by comparison of the query-attribute-positive profiles and the query-attribute-negative profiles; iv) determining a first statistical result indicating the strength of association of the query attribute with attribute combinations having a higher frequency of occurrence in the query-attribute-positive profiles than in the query-attribute-negative profiles; v) expanding one or more of the attributes in the query-attribute-positive profiles and the query-attribute-negative profiles to obtain a second statistical result having a higher strength of association of the query attribute with the attribute combinations containing the one or more expanded attributes.