This practice advisory discusses how the National Prevailing Wage Center (NPWC) determines an occupation's Wage Level when using the OES (Occupational Employment Statistics) survey to make a prevailing wage determination (PWD). Understanding the mechanics of how the NPWC evaluates minimum education, experience, and other requirements when making a PWD based on OES wage data can help you when completing your Form ETA 9141, as well as if you decide to challenge a NPWHC PWD.