1. A method for use in operating a machine-based tool for converting data from a first form to a second form, comprising the steps of: establishing, based on external knowledge of a subject matter area independent of analysis of a particular data set to be converted, a number of schema, each including one or more conversion rules for use in converting data within a corresponding context of said subject matter area; identifying a set of data to be converted from said first form to said second form; determining a particular context of said set of data; based on said context, accessing an associated first schema of said number of schema; and using an included conversion rule of said first schema in a process for converting said set of data from said first form to said second form; wherein said step of establishing comprises identifying a private schema, including conversion rules specific to an entity or group of entities less than the public as a whole, that establishes a structure for understanding at least a portion of the subject matter area.