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Review of WIC Food Packages Improving Balance and Choice: Final Report (2017) / Chapter Skim
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Appendix K: Study Design Strategies for Reducing the Effects of Selection Bias in Studies Comparing WIC Participants to Others
Pages 675-680

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From page 675...
... design compares people who are just below an eligibility threshold for a program or treatment with those who are just above it. Because the likelihood of an individual falling just above or below a threshold is not affected by self-selection, this method yields high internal validation,1 provided that these individuals do not manipulate their presence below or above the threshold (the method typically includes tests for this)
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From page 676...
... . RD designs yield unbiased estimates of the impact of WIC, provided that the identifying assumptions are satisfied for individuals that are right at the eligibility thresholds.2 However, RD designs are not necessarily applicable to the WIC participants with the most need, who might have lower income-to-poverty ratios and may be affected differently by WIC.
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From page 677...
... Larger sample sizes and access to linked WIC administrative data on WIC eligibility and participation would allow for useful outcomes as long as nonparticipants are somehow included. It is also key to have data on individuals who are potentially eligible but not enrolling in the program.
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From page 678...
... and lack of sufficiently detailed longitudinal data on participation over time and on outcomes. Potential USDA-FNS Applications for WIC This approach would be made more useful by encouraging more sharing of WIC administrative data and WIC data from other data systems, including data on families with not all siblings enrolled, as well as data from locations where program changes affect eligibility and enrollment.
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From page 679...
... . In SNAP matters: How food stamps affect health and well-being, edited by J
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Key Terms

  • income threshold
  • wic participation
  • eligibility threshold
  • age thresholds
  • administrative data

  • income thresholds
  • program changes
  • supplemental nutrition
  • wic administrative
  • require researchers

  • fixed effects
  • regression discontinuity
  • study designs
  • income eligibility
  • biases due

  • evaluate wic
  • larger sample
  • presence below
  • food package
  • continuous derivatives

  • income criteria
  • siblings enrolled
  • measured outcomes
  • temporary assistance
  • measurement error

  • linked wic
  • reverse causation
  • automatic wic
  • package implementation
  • wic data


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