Since 1992, FNS has produced biennial reports on WIC participant and program characteristics based on the WIC Minimum Data Set compiled from state management information systems. The 20 items included in the MDS are collected as part of ongoing WIC operations and consist primarily of in formation related to participant eligibility.

The purpose of the study was to learn the extent to which retail grocers, defined as "vendors" in the WIC Program, authorized to provide food to WIC participants, were violating program rules and procedures, and to determine which programmatic and/or demographic variables could be associated with vendor violations.