After the National Agricultural Statistics Service confirmed an error in industry reporting of nonfat dry milk data, NASS issued revisions on April 13, 2007 to previously published data for the weeks of March 31, March 24, and March 17. To determine the extent of the misreporting, NASS subsequently conducted a special data validation of all qualifying nonfat dry milk plants for the period covering April 29, 2006 to April 14, 2007. As of the date of this publication, NASS has contacted all plants with sales of nonfat dry milk in order to review reporting criteria, verify previously reported data, and make any necessary revisions. During the verification process, five firms made revisions to previously reported price and volume data for nonfat dry milk. These changes are included in this report. The revisions resulted in changes ranging from -0.8 to 8.5 cents per pound in the NASS-reported weekly average price of nonfat dry milk. The Dairy Market Enhancement Act of 2000, U.S. Code Title 7, Section 1627, requires mandatory reporting of the price, quantity, and moisture content of butter, nonfat dry milk, cheddar cheese, and dry whey. Dairy products prices data, collected weekly by NASS, are used by USDA to assist in the determination of the fair market value of raw milk. These data are also used to implement the National Dairy Support Program. Each week, NASS surveys plants that produce and sell more than one million pounds of nonfat dry milk annually. Specific, detailed criteria must be met for sales to qualify as usable data. Reporting rules were established to allow standard price discovery that best reflects current market conditions. At the end of this publication are details on what information is included and excluded from the weekly reporting process of nonfat dry milk.