The National Survey of WIC Participants (NSWP) study series is designed to describe state and local agency characteristics, examine participants’ characteristics, assess participants’ experiences with WIC, and estimate improper payments resulting from certification errors in WIC. The study is conducted approximately every 10 years, and the current study is the third iteration (NSWP-III) in the series. 

This report addresses actions taken by the Food and Nutrition Service to comply with the Consolidated Appropriations Act 2021 (PL 116-260, HR 116-446), which directs USDA to conduct a review of existing evidence and develop a plan to explore how participation in WIC is associated with maternal mortality, with emphasis on the needs of disadvantaged communities of color.

This study primarily uses 2011–2016 National Health and Nutrition Examination Survey (NHANES) data to examine bivariate relationships between reported WIC participation and outcomes including diet quality, indicators of nutrition and health, food consumption patterns, and nutrient intakes among 1- to 4-year-old children. Most results presented in this report are unadjusted and descriptive only, and do not infer causality. They are intended to contribute to the evidence base needed to inform future research and, subsequently, WIC policy and practice.

This report, the latest in a series of annual reports on WIC eligibility, presents 2018 national and state estimates of the number of people eligible for WIC benefits and the percents of the eligible population and the US population covered by the program, including estimates by participant category. 

​​This report supplements FNS administrative data on total food costs by estimating the average monthly food costs for each WIC participant category and food package type. It also estimates total pre- and post-rebate dollars spent on 18 major categories of WIC-eligible foods in FY 2018.

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.

About every 7 years, FNS performs a nationally representative study to examine the extent of error and abuse among food vendors authorized to accept WIC vouchers. The last bookend study was the 2005 WIC Vendor Management Study, which used fiscal year 2005 expenditure data to derive an estimate for 2004. Between bookend studies, there is a need to derive annual estimates of the level of improper payments for compliance with the Improper Payments Information Act of 2002. The purpose of the subsequent annual studies was to provide annual updates to the bookend studies using the developed aging methodology.

This report, the first of three, addresses the first objective of the study, which is to explore the characteristics and experiences of WIC participants.