A method for verifying a plurality of rules stored in a knowledge base for consistency. The method identifies rules in the knowledge base that are covered or made useless by at least one rule, two rules, or at three rules. Each rule in the database has at least one option and a corresponding range for satisfying the option. Each of the plurality of rules are compiled into a term. The terms are then arranged into a hierarchical listing with high priority terms being placed before low priority terms. Each term is removed from the hierarchical listing with the high priority terms being removed before the low priority terms. Each removed term is then added to a sum of previously removed terms. Then it is determined if the removed term is covered by the terms in the sum of previously removed terms. Coverage is determined by using an interval consensus procedure which uses an absorption rule, a partial absorption rule, a continuation rule, a simplification rule, and consensus rule.