Research has repeatedly found that being a firstborn can come with advantages—they tend to be natural leaders, have higher IQ’s, and are often chosen to portray James Bond. They also perform better in school. This new NBER study sheds light on why this is so, testing the conventional wisdom that earlier-born siblings put more effort in school and perform better than their later-born siblings partly because their parents are more strict with them. Using the 1979 National Longitudinal Survey of Youth (which includes data from parent surveys), they track outcomes for children as they transition between the ages of 10 and 14. Three key findings: First, there is a clear association between school performance and birth order. For example, 34 percent of firstborns are viewed by their mothers as “one of the best in the class,” versus 27 percent of those coming fourth in birth order. Likewise, just 7 percent of firstborns are considered below the middle or at the bottom of the class, compared to 11 percent of fourth-borns. (The analysts use GPAs on school transcripts to validate the moms’ self-reported data regarding how their children perform in school.) Early birth order is also associated with higher scores on standardized math and reading tests. Second, parents regulate earlier-born siblings’ television-viewing and homework-completing behaviors more intensely. Third, the more younger siblings a child has, the more likely are his parents to closely supervise him in the event that he brings home low performance on a report card. For instance, within a family of four, the first born is 6.6 percentage points more likely to have the parent be “very likely” to punish him for bad grades, relative to the last born. (They control for a variety of confounding variables, such as family size and disruption in the family structure.) Now we have a plausible explanation of how parental behavior could at least partially explain why we see birth-order effects relative to student performance—and a clear message to parents: don’t let your high expectations flag when your younger children come along!

SOURCE: V. Joseph Hotz and Juan Pantano, “Strategic Parenting, Birth Order, and School Performance,” NBER Working Paper 19542, October 2013.