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.

FNS published “The WIC Vendor Management Study, 1998” in July 2001 which examined, in part, the extent to which retail grocers, defined as WIC “vendors” were violating program rules and regulations. The 1998 study is a follow-up to the “WIC Vendor Issues Study, 1991” published by FNS in May 1993.