What’s more, it could even undermine a future Ph.D.’s potential lifetime earnings. Based on their analysis of approximately 14,500 freshly minted Ph.D. recipients, the researchers conclude that a student who isn’t redshirted could end up earning $138,000 more over the course of his or her lifetime than someone who is. Assuming redshirted students get their doctorates a year later than they would’ve had they not had their schooling delayed, they get a year’s head start on their salaries, which for a first-year Ph.D. recipient averages about $58,000. “The compounding effect” of that $58,000, namely annual inflation over 30 years, causes that difference to accumulate.

These findings clearly offer striking contradictions to previous analyses. And in a way that only complicates efforts to draw conclusions about redshirting. After all, a lot can happen over the course of a child’s educational trajectory: The age at which that child learns how to write the alphabet and count to 100 is just one among an infinite number of factors that could wind up determining his or her success, many of which are nearly impossible to control. Still, despite the cost of an extra year of childcare and the muddled research on its merits, parents continue to redshirt “as a voluntary act to gain a comparative advantage,” write Kniffin and Hanks, while others even time pregnancies to ensure their kids are relatively older than their peers.

The new study is compelling enough to suggest that all the kindergarten-age hullabaloo is, at the very least, a tad overblown. “People who were or are relatively among the youngest in their classes shouldn’t feel stigmatized or disadvantaged because of their age,” Kniffin said, noting that he and Hanks deliberately made the study free for anyone to access to ensure laypeople can peruse its findings, too. “We would like to think that [with] this evidence, parents would feel a little less anxiety; it should provide a dose of anti-anxiety medicine for them.”

But it seems unlikely that the new study will actually help parents loosen up as much as Kniffin would like. Many of today’s savvy child-rearers are entrenched in a cycle that starts with what some have coined “The Rug Rat Race,” employing a plethora of tactics aimed at giving their kids a competitive edge by the time they reach college. And in some ways that’s often because they feel like they don’t have much of a choice. Roughly half of all states now require schools to conduct kindergarten-readiness exams—as do selective private schools, where even kindergarten can easily cost thousands of dollars in tuition. “So-called success in school is a high-stakes enterprise that weighs on the minds of parents from the time the baby is born, or even sooner,” writes the Vanderbilt professor Stephen Camarata in his new book The Intuitive Parent.