A performance specification states requirements in terms of the required results and the criteria for verifying compliance, without specifically stating how the results are to be achieved.

The performance work statement (PWS) serves as the foundation for the request for proposals (RFP) or invitation for bids (IFB) and resultant contract. It explains what is to be accomplished in terms of results so that the U.S. Government can monitor and evaluate the progress and final result of the project effectively.

Performance requirements define how the system should perform. A performance requirement is generally measured in quantity, accuracy, coverage, timeliness, or readiness.