If you’ve read Malcolm Gladwell’s Outliers, you probably remember the argument he makes in the book’s first chapter: In competitive situations, a person who’s relatively older than the others will probably be the one who wins.

Gladwell centers on a real-world example in which almost all of the players who had been selected for a Canadian Hockey League team had birthdays in the first four months of the year. Why? In Canada, Gladwell reasons, the cut-off age for participating in the sport is almost always January 1. A child who, say, turns 11 on January 4 would still play alongside a child who turns 11 much later in the year—and at that stage in life, there are typically significant distinctions in physical characteristics and abilities between two such kids. Gladwell concludes that in Canada, the world’s hockey capital, this policy puts the two children on two very different paths from the get go; the older, more physically developed one gets selected for all-star teams, which means better coaching, resources, and practice opportunities, and, ultimately, a better shot at the pros.

This phenomenon, according to the 2008 book, extends far beyond Canada and hockey. Hence, Gladwell’s famous case for academic redshirting: the increasingly popular parental practice of delaying kids’ entrance into kindergarten. According to some research, between 4 percent and 9 percent of kindergartners are redshirted annually. And while some scholars have suggested that redshirting doesn’t do much of anythingat least in the long run—Gladwell contends that this assumption is false. Rather, this dynamic persists in insidious ways, locking “children into patterns of achievement and underachievement, encouragement and discouragement, that stretch on and on for years,” he writes, pointing to a widely cited 2006 study that found that cut-off dates can even have an impact on whether or not a child ends up going to college.

The Outliers and the 2006 study are often credited with putting redshirting on the public’s radar. But some experts say its origins trace back as far as the 1980s, amid increases to kindergarten-age requirements and shifts in parenting culture. Up until then, kindergarten was seen as a lighthearted environment where youngsters would be engaged in playful, creative activities while being gradually acclimated to basic academic topics (like shapes and colors) and skills (holding a pencil and using glue). Kindergarten attendance still isn’t required in 35 states, and nearly a fourth of kindergartners nationwide are only enrolled in half-day programs. Despite all that, early-childhood education has become a source of some of the most polemical debates surrounding American schooling.

The emphasis on high-stakes testing of education-reform initiatives such as No Child Left Behind exacerbated what researchers in 1988 identified as escalating academic demand in kindergarten classrooms. In part because of those public-policy changes, though also because of fiscal incentives and mindset changes, more and more states started moving up their cutoff dates. In 1975, just nine states required students to be 5 by the start of the school year; by 2005, the number had grown to 33. Data from 2008 shows that 17 percent of children entering kindergarten that year were 6 years or older.

Arguments for redshirting abound in academic journals, opinion pages, and parenting forums; arguments attempting to debunk those those theories are almost just as widespread. On top of a slew of academic studies, it’s been the subject of multiple posts in The New York Times “Motherlode” blog, as well as The Wall Street Journal, Slate, and ABC’s Good Morning America, among others. The Huffington Post even has an entire landing page devoted to the topic. It’s clear parents (and educators and economists and policymakers) want a verdict on the merits of the practice.

There are scholars who echo Gladwell’s conclusions, arguing, for example, that relatively young students are disproportionately diagnosed with learning disabilities or more likely to underperform on standardized tests. Yet there are other scholars who contend that relatively older students are more likely to drop out of high school or commit a felony offense by age 19 or that they tend to have slightly lower overall educational attainment. One study, meanwhile, found that age diversity in kindergarten classrooms is beneficial in itself; relatively young students, it suggested, have better outcomes when they’re learning alongside relatively older peers.

A new study published in the journal Contemporary Economic Policy offers perhaps the latest piece of evidence that redshirting is little more than a silly fad—or, as one pair of economists put it in 2009, a “suburban legend.” The new study, by Cornell’s Kevin Kniffin and Ohio State’s Andrew Hanks, looks at whether redshirting influences the likelihood that a child will eventually obtain a Ph.D. The fact that this degree is held by less than 2 percent of the U.S. population makes it a meaningful metric, the researchers say, because it reflects an exceptional combination of academic achievement and ambition; its exclusivity also makes it somewhat comparable to Gladwell’s hockey-selection data. The study found that redshirting has virtually no impact on Ph.D. attainment.

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.

This parenting phenomenon—and its unintended socioeconomic consequences—is where Kniffin and Hank’s study may hold particular relevance. Parents redshirt for a variety of reasons, typically because they fear their children aren’t adequately prepared for kindergarten. The concern is understandable, and often valid, given the range of developmental patterns at that age. And it makes sense that the practice is most common for children born within a month of the given state’s kindergarten cutoff date. (Children’s developmental variation also helps explain why state kindergarten-age policies—which range from July 31 of the year a child enters school to January 1 of the school year—can be so controversial.)

Nonetheless, redshirting is most prevalent among highly educated parents, as they’re the ones who are most likely to be aware of school-entry laws. These families are also the most likely to send their children to preschool—and afford an extra year of tuition. Children whose mothers have bachelor’s degrees or higher are almost twice as likely as those whose mothers have less than a high-school diploma to attend a center-based preschool program (79 percent versus 43 percent), according to a recent report from The Century Foundation and the Poverty & Race Research Action Council. That could ultimately mean that, for many of the parents who opt to redshirt, their fear of sending underprepared children to kindergarten “is all a bit of a tempest in a teapot,” as the Cleveland-based New York Times contributor Sharon Holbrook put it earlier this year.

In fact, redshirting could mean that a preschool-educated 6-year-old is learning alongside a low-income 4-year-old who’s never stepped foot in a classroom—a kid whose vocabulary may be 30-million words smaller than her wealthier peers. Even if that 6-year-old was indeed a little “underdeveloped” at age 5, delaying his entry into school could contribute to the kind of incongruity that fuels detrimental discrepancies in achievement—gaps that expand and evolve over time. The Society for Research in Child Development reported in 2002 that, notwithstanding some evidence in favor of redshirting, doing so may be “disadvantageous for low-income children, who already begin school with relatively poor cognitive skills.”

So, while it may not clear up the redshirting debate, the new research might help spur the socially conscious parent to resist the temptation to redshirt—on the grounds that doing so is not only unnecessary but can put educational attainment further out of reach for the child’s less-fortunate peers. Maybe The Outliers is right in “drawing attention to [the] ways in which individual success is interdependent within an ‘ecology’ of others’ activities,” suggest Kniffin and Hanks. But it’s far from clear whether relative age has much to bear on a child’s future success. And absent a consensus, it may be best to hold off on redshirting, if only in the interest of playing it safe.

As Kniffin concluded, the new study’s findings suggest that “parents can relax a little.” In fact, perhaps the key takeaway is that they should.