The Supplemental Nutrition Assistance Program (SNAP) is the cornerstone of food assistance in the United States. Begun as a small pilot known as the Food Stamp Program in 1963, today it reigns as one of the largest means-tested transfer programs in the social safety net, serving over 42 million persons in an average month during 2017, at a total annual cost of $68 billion. In 2013 UKPR co-organized a conference on the 50th anniversary of SNAP with the Institute for Research on Poverty and Brookings Institution, with the support of the Annie E. Casey Foundation, the Ford Foundation, and the Economic Research Service in USDA. The conference resulted in an edited volume published in 2015 called SNAP Matters: How Food Stamps Affect Health and Well Being. Among other things, the volume provides strong evidence that SNAP is highly responsive to macroeconomic pressures as well as to policy choices intended to enhance access among low-income households. As a result, it has become one of the most effective antipoverty programs overall, and is particularly effective at lifting non-elderly households with children out of deep poverty. As highlighted in the discussion papers below, UKCPR has also sponsored numerous additional studies on SNAP via its Research Program on Childhood Hunger, along with the FoodAPS, NHIS, and PSID research initiatives.




Estimating the associations between SNAP and food insecurity, obesity, and food purchases with imperfect administrative measures of participation

Administrative data are considered the “gold standard” when measuring program participation, but little evidence exists on the potential problems with administrative records or their implications for econometric estimates. We explore issues with administrative data using the FoodAPS, a unique dataset that contains two different administrative measures of Supplemental Nutrition Assistance Program (SNAP) participation as well as a survey-based measure. We first document substantial ambiguity in the two administrative participation variables and show that they disagree with each other almost as often as they disagree with self-reported participation. Estimated participation and misreporting rates can be meaningfully sensitive to choices made to resolve this ambiguity and disagreement. We then explore sensitivity in regression estimates of the associations between SNAP and food insecurity, obesity, and the Healthy Eating Index. The signs remain the same regardless of the SNAP participation measure used, and the coefficient estimates are in most cases not statistically different from each other. However, there are some meaningful differences in the magnitudes of the estimates and their levels of statistical significance. 

The effect of SNAP and the broader safety net on mental health and food insecurity

Previous literature documents a strong relationship between food insecurity and mental health, and also examines the impact of safety net programs on food insecurity.  However, little is known about the intersection between mental health, safety net participation, and food insecurity. In this research, we use a multi-program safety net calculator (including cash, food, and health insurance programs) and data from the National Health Interview Survey and the Current Population Survey to examine the effects of safety net generosity on food insecurity and mental health for single mother families.  We examine four research questions.  First, does state safety net generosity affect self-reported participation in safety net programs?  Second, does mental health affect participation in safety net programs, conditional on generosity?  Third, does more generous cash and food assistance affect mental health? And finally, how effective is the safety net in reducing food insecurity in the presence of mental health issues? We find that state-level safety net generosity does predict self-reported participation, and that conditional on generosity, those with mental health issues are significantly more likely to participate in safety net programs.  More generous cash and food assistance is protective of maternal mental health, but results are somewhat sensitive to the measure of mental health examined.  Finally, we find no effect of the safety net on 30-day food insecurity.  These results have important implications for the effectiveness of safety net programs for some of the most vulnerable members of society: low-income mothers suffering from mental health challenges and their children. 

Food security, health, and healthcare utilization: The role of SNAP for families in extreme poverty

We study whether SNAP mediates the effect of food insecurity on future health and healthcare utilization more for the extreme poor (i.e., those with income below 50% of the poverty line) than it mediates the effect for other low-income families (i.e., with incomes between 50% and 200% of the poverty line). We use data for about 23,000 people in the 2011-2012, 2012-2013, and 2013-2014 linked NHIS-MEPS surveys with the measures of food insecurity coming from the NHIS and the measures of SNAP benefits and various health outcomes from the MEPS. We find that SNAP significantly reduces the negative effects of food insecurity on several measures of health and healthcare-related outcomes for nonelderly adults, and that this reduction is often significantly greater for those in extreme poverty. However, we find no significant effects of this type for children. In addition, attempts to control for possible endogeneity of the SNAP effect of interest are unsuccessful because of a lack of strong instruments. Nevertheless, endogeneity of the effect of interest maybe biased downward, strengthening the support of the OLS estimates as valid.


How well does SNAP protect families against the risk of food insecurity and poor health during economic downturns?

Our research project addressed the question of how well SNAP and the social safety net protects families against the risk of food insecurity and poor health during economic downturns. Previous research has documented the relationship between reductions in family incomes and food insufficiency and has examined the effects of resources that mitigate the effects of income volatility. The U.S. social safety net, including SNAP, exists to mitigate the deleterious effects of swings in family income, particularly among low- and moderate-income households. This work compares outcomes for lower income families and higher income families in response to economic downturns. To the extent that nutritional, food security and food-related health outcomes are unaffected by economic downturns, there is implicit evidence that the social safety net is working to protect economically disadvantaged families.

Using natural experiments to identify the effects of SNAP on child and adult health

The Supplemental Nutrition Assistance Program (SNAP; formerly known as food stamps) can have important impacts that extend beyond its intended aims to improve food security and nutrition, particularly for health and health care use. This project examined the impact of SNAP receipt and benefit level on the health of adults and children using two natural experiments to address selection bias: 1) state policy variation in SNAP in an instrumental variables (IV) analysis; and, 2) the temporary expansion of SNAP benefits and eligibility provided through the American Recovery and Reinvestment Act (ARRA) in a difference-in-difference (DD) approach. We used restricted data from the National Health Interview Survey (NHIS) from 2008 to 2014, restricting our sample to persons in SNAP-eligible and low-income SNAP-ineligible households. The IV analysis suggests that SNAP receipt is associated with improved health and reductions in foregone medical care due to affordability among adults and children. However, we find little evidence that ARRA’s temporary benefit increase led to any changes in health or health care use. Whereas SNAP receipt may improve health and health care use for populations close to the eligibility threshold (and thus induced to participate by some policies), the relatively small increase and reduction in SNAP benefits may not have been substantial enough to change health outcomes.

The real value of SNAP benefits and health outcomes

The food stamp program (SNAP) is one of the most important elements of the social safety net and is the second largest anti-poverty program for children in the U.S. (only the EITC raises more children above poverty). The program varies little across states and over time, which creates challenges for quasi-experimental evaluation. Notably, SNAP benefit levels are fixed across 48 states; but local food prices vary widely, leading to substantial variation in the real value of SNAP benefits. In this study, we leverage time variation in the real value of the SNAP benefit across markets to examine the effects of SNAP on child health. We link panel data on regional food prices and the cost of the Thrifty Food Plan, as measured by the USDA’s Quarterly Food at Home Price Database, to restricted-access geo-located National Health Interview Survey data on samples of SNAP-recipient and SNAP-eligible children. We estimate the relationship between the real value of SNAP benefits (i.e., the ratio of the SNAP maximum benefit to the TFP price faced by a household) and children’s health and health care utilization, in a fixed effects framework that controls for a number of individual-level and region characteristics, including non-food prices. Our findings indicate that children in market regions with a lower real value of SNAP benefits utilize significantly less health care, and may utilize emergency room care at increased rates. Lower real SNAP benefits also lead to an increase in school absences but we find no effect on reported health status.


The influence of SNAP participation and food environment on nutritional quality of food at home purchases

A growing body of research describes how individuals make food shopping decisions in both time and space. The FoodAPS dataset provides a unique opportunity for understanding these patterns among a large sample across income, SNAP status, and settings. We addressed three questions in our research: (1) Where do participants shop for food at home (FAH) and how do individual characteristics interact with store characteristics and distance? (2) How does the nutritional content of foods purchased change as time from SNAP distribution increases? and (3) How does store choice influence the nutritional quality of FAH purchases? We used a conditional logit model to answer the first question, determining that overall, participants choose full-service supermarkets, larger stores, and stores closer to home but that store choice is influences by SNAP status, ethnicity, race, sex, car ownership and the level of urbanization of the county of residence. For the second question, we used general linear modeling to determine changes over time in dietary quality of FAH purchases, as measured by composite Health Eating Index (HEI) score. We found an increase in HEI-2010 score in the days immediately following SNAP distribution followed by a decrease until 20 days after distribution and then a moderate increase to the end of the SNAP-cycle. For the final question, we used a generalized estimating equation (GEE) model for repeated-measures to analyze the impact of store type on composite HEI score of FAH events. We found that purchases made at limited assortment stores had significantly higher HEI scores while dollar stores had significantly lower HEI scores than purchases at conventional supermarkets. Participating in SNAP had significant positive impact on composite HEI scores, relative to households income-eligible for SNAP but not participating. These results require closer consideration but have important implications for policies relating to what types of foods stores should be subsidized, through healthy food financing initiatives and SNAP and WIC authorization, and the way SNAP benefits are distributed over the course of the month.

Variation in food prices and SNAP adequacy for purchasing the thrifty food plan

Whether Supplemental Nutrition Assistance Program (SNAP) benefits are adequate to provide food security for eligible households is an important and timely policy question. While the nominal value of SNAP benefits is fixed across states (except for Hawaii and Alaska), variation in food prices across geographic areas is dramatic, and the real value of SNAP benefits varies widely across the U.S. Our research provides new evidence on geographic variation in the adequacy of SNAP benefits to purchase the Thrifty Food Plan (TFP). Using multiple methods to estimate the cost of the Thrifty Food Plan (TFP) faced by households across the nation, and several measures of the SNAP benefits available to them, we consistently find that a substantial fraction of SNAP-recipient households receive benefits that are insufficient to purchase the TFP. Our primary estimates indicate that SNAP benefits (plus 30 percent of income) are insufficient for approximately 20-30 percent of households to purchase the TFP. Sufficiency rates increase monotonically as we expand the distance within which the household is assumed to be able to shop. For households who are unable to afford the TFP, average dollar shortfalls between the cost of the TFP and SNAP benefits (plus 30 percent of income) are often as large as $150 per month. When shoppers are assumed to be able to purchase the TFP at the minimum-cost store in the area, SNAP benefits are sufficient for over 90 percent of households. However, this assumption seems unlikely to hold for many SNAP households.

The relationship between neighborhood food environment and food store choice on purchasing habits among SNAP and lower income households

The objective of the study was to determine relationship between neighborhood food store availability, store choice and food purchasing habits among Supplemental Nutrition Assistance Program (SNAP) participating households. The study sample consisted of SNAP households (n=1581) and low income households participating in the USDA's National Household Food Acquisition and Purchase Survey (FoodAPS) a nationally representative cross-sectional survey of American households with household food purchases and acquisitions data. Main Outcomes: 1) Food purchasing choices (sugar-sweetened beverages, fruits and vegetables, snacks, water, and milk) obtained from store receipts over a one-week period; 2) food shopping activities was obtained from a log book of where food was purchased over a one-week period. Key findings indicated those SNAP households within 1 mile of a supermarket had higher odds of shopping at a supermarket (2.05 OR ) compared to those without a supermarket. Shopping at a supermarket was associated with greater odds of purchasing water and low-calorie beverages (OR 1.69 ) and fruits and vegetables (OR 2.50 (95% CI 1.52, 4.11]) compared to not shopping at supermarket among SNAP households. Additionally, a fractional multinomial logit analysis (n=4,664) similarly found that close proximity to superstores or supermarkets increases the share of weekly food purchases made there, and that car access increases purchases made at restaurants while decreasing purchases made at other food shopping venues. Findings suggest that policies aiming to improve food purchasing habits among SNAP need to consider how to situate stores where SNAP households will choose to shop.

The effects of benefit timing and income fungibility on food purchasing decisions among SNAP households

The Supplemental Nutrition Assistance Program (SNAP) is the largest nutritional safety net in the United States. Prior research has found that participants have higher consumption shortly after receiving their benefits, followed by lower consumption towards the end of the benefit month. This “SNAP benefit cycle” has been found to have negative effects on beneficiaries. We examine two behavioral responses of SNAP participants that may work in tandem to drive much of the cycle: short-run impatience – a higher preference to consume today; and fungibility of income – the degree of substitutability between a SNAP dollar and a cash dollar. Using data from the National Food Acquisition and Purchase Survey (FoodAPS), we find evidence of both behavioral responses. The degree of short-run impatience and fungibility of income is found to differ significantly across poverty levels and use of grocery lists to plan food purchases. Food purchase planning education could be used to counter the observed benefit cycle. Deeper analysis of the purchase data suggests that the benefit cycle is primarily associated with a decrease in the purchase of healthful and perishable foods—which could lead to lower dietary quality. We also find evidence that suggests households compensate for the effects of the SNAP benefit cycle by acquiring free food, primarily from schools. This highlights the importance of programs like the National School Lunch Program for SNAP households.