In the Phase I report, the panel also concluded that, overall, current methods used to estimate WIC eligibility substantially underestimate the number of people eligible for WIC. This conclusion was based in part on the panel’s estimates of adjunctive eligibility, but also on other methodological issues that the panel identified as contributing to an understatement. Specifically, the panel also found that current assumptions about the accounting time period for measuring income and the definition of an economic unit for determining eligibility, along with the underestimation of infants in the CPS, contribute to an overall underestimate of WIC eligibility. Although the incorrect data used to estimate the numbers of Medicaid enrollees used in the Phase I report led to an overstatement of the size of this underestimation, the general conclusion that current methods result in an underestimation of eligibility for WIC is still supported.

The results with the corrected 1998 data will be included in the panel’s final report. The panel will use the TRIM data from other years (1994, 1996, and 1999) to estimate the effect of accounting for adjunctive eligibility on WIC eligibility estimates. The panel is also conducting a more detailed analysis of the TRIM simulations of Medicaid participation and will examine the stability of the estimates of adjunctive eligibility over time and the characteristics of those who are simulated as Medicaid participants. These analyses will be conducted as a further check of the results reported in Phase I.

The panel regrets the error reported in the Phase I report. I invite you to contact me if you have any questions about the data or the panel’s work.


David Betson

Chair, Panel to Evaluate the USDA Methodology for Estimating Eligibility and Participation for the WIC Program

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