The National School Lunch Program: Seasonal Difference in Program Participation and Program Impacts on Food Insufficiency and Food Insecurity

Year: 2014

Research Center: Institute for Research on Poverty, University of Wisconsin-Madison

Investigator: Huang, Jin

Institution: Saint Louis University

Project Contact:
Jin Huang
Saint Louis University
College for Public Health and Social Justice
Tegeler Hall, Room 211
3550 Lindell Boulevard
St. Louis, MO 63103
Phone: 314-977-2750


The purpose of the National School Lunch Program (NSLP) is to ensure that low-income, school-aged children have access to adequate nutrition and to mitigate the problems associated with malnourishment among children. Children from families with incomes at or below 130 percent of the Federal poverty level are eligible for free meals; those from families with incomes between 130 percent and 185 percent of the poverty level are eligible for reduced-price meals at a rate of less than 40 cents. Although it is consistently found that the NSLP participation increases children’s dietary intakes, it is unclear to what extent the NSLP reduces food insecurity among children and their families.

One challenge to assess the impact of the NSLP on food insecurity is the potential selection problem that households with a high risk of food insecurity are more likely to participate in food assistance programs. Since the NSLP is operated in schools, the program does not provide services in summer months when school is not in session, which creates a seasonal difference in program participation. The fact that children do not participate in the program in summer months is a result of program rules, and is by no means related to participants’ self-selection into the program. This study examines the impact of receiving free/reduced-price lunch from the NSLP on food insecurity and food insufficiency among low-income children (ages 5 to 18 years) using the seasonal difference in the NSLP participation.

The study uses four panels (1996, 2001, 2004, and 2008) of the Survey of Income and Program Participation (SIPP), which provides information on food insecurity and insufficiency in both summer (June to August) and nonsummer months. The SIPP includes a food insufficiency question and a five-item food insecurity scale in the adult well-being topical module in at least one wave of interviews (i.e., Wave 8 in the 1996 and 2001 panels, Wave 5 in the 2004 panel, and Waves 6 and 9 in the 2008 panel). As the SIPP sample is randomly divided into four rotation groups and the same wave of interview is conducted in four consecutive calendar months for these groups, the SIPP collects the information on food insufficiency and food insecurity in seven calendar months across four groups. Within each rotation group, the information of household food hardship may cover both summer and nonsummer months (within-group variation). In addition, the number of summer months included in the reference period varies by rotation group (between-group variation). This design provides a unique opportunity to examine the impacts of the NSLP on food insufficiency and food insecurity using the seasonal difference in program participation.

The study creates two samples from the SIPP. The first sample includes households with children between ages 5 and 18 years and with at least one child receiving free/reduced-price lunch (N = 15,242). The study examines the impact of the NSLP on food insufficiency among recipients of free/reduced-price lunch using a fixed-effect ordinary least squares (OLS) regression model. The second sample instead includes households with children ages 5 to 18 years and with income lower than 185 percent of the poverty line (N = 18,378). All households in the second sample are eligible for free/reduced-price lunch from the NSLP. The study assesses the impact of the NSLP on food insecurity using a difference-in-difference approach.

Among households receiving free/reduced-price lunch, the food insufficiency rate in the reference period is nearly 7 percent and the monthly food insufficiency rate is 3.9 percent. About one-quarter of households have food insecurity in the reference period, and 10 percent of households experience very low food security. Among households eligible for free/reduced-price lunch, the food insufficiency and food insecurity rates in the reference period are 6.3 percent and 23 percent, respectively. Results of fixed-effect OLS regressions on recipients of free/reduced lunch suggest that the dichotomous indicator of summer months is positively related to the probability of food insufficiency (b = .006), statistically significant at the .01 level. For households with children receiving free/reduced-price lunch, the monthly food insufficiency rate is 0.6 percentage points higher in summer months than that in nonsummer months. The difference-in-difference analysis on households eligible for free/reduced-price lunch finds that one more summer month in the reference period increases the difference in food insecurity rates between recipients and nonrecipients eligible for free/reduced-price lunch by 1.5 percentage points (p < .01). This result indicates recipients suffer more from food insecurity in summer when the NSLP is not available.