This report provides improper payment estimates for fiscal year 2011 using a methodology for “aging” the 2005 bookend study. The methodology yields nationally representative estimates of the number of vendors that over- and undercharged and the amount of over- and undercharges across all WIC vendors.

This report provides improper payment estimates for FY 2010 using a methodology for “aging” the 2005 bookend study. The methodology yields nationally representative estimates of the number of vendors that over- and undercharged and the amount of over- and undercharges across all WIC vendors.

This report provides improper payments estimates for FY 2009 using a methodology for “aging” the 2005 bookend study. This updates previous reports providing estimates from 2005 to 2008.