The efficiency with which a system achieves a particular recall ratio. A measure of how much work one must do to sort records after the search is done. High precision indicates that most of the items you retrieve are relevant. Boolean AND as well as Boolean NOT searching results in higher precision and lower recall.

How well does a search retrieve ALL POSSIBLE RELEVANT RECORDS.High recall indicates that you have retrieved most of the available relevant records in a databases (and possibly a large amound of IRRELEVANT records - see precision). Boolean OR searching results in higher recall and lower precision.