This paper investigates how accountability pressures under No Child Left Behind (NCLB) may have affected students’ rate of overweight. Schools facing pressure to improve academic outcomes may reallocate their efforts in ways that have unintended consequences for children's health. To examine the impact of school accountability, we create a unique panel dataset containing school-level data on test scores and students’ weight outcomes from schools in Arkansas. We code schools as facing accountability pressures if they are on the margin of making Adequate Yearly Progress, measured by whether the school's minimum-scoring subgroup had a passing rate within 5 percentage points of the threshold. We find evidence of small effects of accountability pressures on the percent of students at a school who are overweight. This finding is little changed if we controlled for the school's lagged rate of overweight, or use alternative ways to identify schools facing NCLB pressure.

We estimate the effects of relative age in kindergarten using data from an experiment where children of the same age were randomly assigned to different kindergarten classmates. We exploit the resulting experimental variation in relative age in conjunction with variation in expected kindergarten entry age based on birthdate to account for negative selection of some of the older school entrants. We find that, holding constant own age, having older classmates on average improves educational outcomes, increasing test scores up to eight years after kindergarten, and raising the probability of taking a college-entry exam. These findings suggest that delaying kindergarten entry, or so-called academic “redshirting,” does not harm other children—and may in fact benefit them—consistent with positive spillovers from higher-scoring or better-behaved peers.

Research based on randomized experiments (along with high-quality quasi-experiments) has gained traction in education circles in recent years. There is little doubt this has been driven in large part by the shift in research funding strategy by the Department of Education's Institute of Education Sciences under Grover Whitehurst's lead, described in more detail in his article in this issue.