The goal of this paper is to assess the existing state of knowledge about whether SNAP improves health and nutrition outcomes, and if so, which ones and by how much.

In an era of fiscal crisis, knowing whether SNAP has any significant causal effect on health and nutrition is crucial for informing policy decisions and policy makers. In this review, I pay particular attention to the challenges researchers face in overcoming selection bias and identifying causal effects of the program, and I will assess the literature through that lens. The fundamental challenge in program evaluation in general and in assessing the impact of SNAP in particular is that participants are not selected at random from the population. Thus, comparisons of those who use SNAP and those who do not—even conditional on observable characteristics—may not be apples to apples comparisons. To the extent that those who choose to participate in SNAP are negatively selected—as one might expect— SNAP recipients are likely to be less healthy, and thus possible positive estimates of the effects of SNAP could be biased downward.

Document Type

Research Paper

Publication Date


Discussion Paper Number

DP 2014-02