Facilitating a user determination of an exclusion keyword in order to specify an efficient exclusion of an unwanted piece of data when the user narrows searching objects. Exclusion is accomplished in a system having a searching object data storage for storing pieces of searching object data, a searcher for performing a primary narrowing of the search, a common keyword extractor for extracting the common keywords associated with a piece of data, an input/output device for passing a selected keyword selected the extracted common keywords while receiving and displaying a result from an exclusion efficiency calculator. The exclusion efficiency calculator calculates exclusion efficiency and indicates a level of exclusion efficiency of data that is not associated with a selected keyword for an individual common keyword.