Methods, systems and computer instructions on computer readable media are disclosed for optimizing a query, including a first join path, a second join path, and an optimizer, to efficiently provide high quality information from large, multiple databases. The methods and systems include evaluating a schema graph identifying the join paths between a field X and a field Y, and a value X=x, to identify the top-few values of Y=y that are reachable from a specified X=x value when using the join paths. Each data path that instantiates the schema join paths can be scored and evaluated as to the quality of the data with respect to specified integrity constraints to alleviate data quality problems. Agglomerative scoring methodologies can be implemented to compute high quality information in the form of a top-few answers to a specified problem as requested by the query.