1. A method of programmatically determining an effect of one or more query criterion on results returned by executing a query containing the one or more query criterion, comprising: receiving results from executing the query against a data source; programmatically building a modified form of the query by removing at least one query criterion from the query; receiving results from executing the modified form of the query; and determining an effect of the at least one query criterion on the results received from executing the query against the data source relative to results received from executing the modified form of the query.