The Healthy, Hunger-Free Kids Act of 2010 was intended to improve student health and reduce childhood obesity by increasing the minimum nutritional standards that schools must meet. Despite its good intentions, the changes mandated by this act were met with immediate backlash. In response to the criticism and as part of its commitment to repeal a host of Obama-era regulations, the Trump administration recently put a stop to some of the new standards.
But could returning to the days of anything-goes in school cafeterias negatively impact student achievement? The results from a recent NBER study suggest it’s possible. In the past, analyses of school meals have been limited to examinations of whether providing meals can increase test scores (it does). This study is unique because it investigates whether the nutritional quality of meals can boost test scores.
The researchers examined a dataset of California public elementary, middle, and high schools that report state test results. From there, they determined whether these schools had a contract with a private meal provider. In total, approximately 143 districts overseeing 1,188 schools—12 percent of California’s public schools—did so, contracting with a total of forty-five different vendors. The remaining 88 percent of California’s public schools utilized “in-house” staff to prepare meals.
Next, trained nutritionists from the Nutrition Policy Institute determined the quality of vendors’ school lunches by using a modified version of the Healthy Eating Index (HEI), a measure of diet quality that’s used by the U.S. Department of Agriculture to determine relationships between diet and health-related outcomes. Vendors with an HEI score above the median vendor score were labeled healthy vendors, while those with below median HEI scores were labeled standard vendors.
For student achievement data, researchers used California’s Standardized Testing and Reporting (STAR) assessment, which was the statewide test until 2013-14. STAR was administered to all students in grades two through eleven each spring, and covered the four core subject areas as well as a set of end-of-course high school exams. Researchers used these data to create a single composite test score for each year and each school grade.
After controlling for various factors, results show that contracting with a healthy vendor increased student test scores by .03 to .04 standard deviations on average relative to in-school meal preparation. In laymen’s terms, that's a boost of about 4 percentile points. The findings also show modest evidence of larger effects for economically disadvantaged students than for non-disadvantaged students. Healthy cafeteria vendors did not cost dramatically more than in-house preparation. Researchers also found that switching from in-house meal prep to a healthy lunch vendor would raise a student’s test score by 0.1 standard deviations for only $258 per year. By comparison, the Tennessee STAR experiment—which reduced class size in grades K-3—cost $1,368 per year to raise a student’s test score by the same amount.
Aside from increased student achievement and low cost, the report offers a few additional data points. First, it found no evidence that hiring a vendor to serve healthier meals led to a change in the number of lunches sold. Second, healthy meal vendors did not reduce the percentage of students who are overweight, although the researchers note that “a longer time period may be necessary to observe improvements in health.” For schools looking to increase student achievement without spending a fortune, investing in healthy meals seems like a cost-effective solution.
SOURCE: Michael L. Anderson, Justin Gallagher, Elizabeth Ramirez Ritchie, “School Lunch Quality and Academic Performance,” National Bureau of Economic Research (April 2017).