Frogpond Effects: Age and Kids' Long-Term Academic Outcomes

Redshirting is not just for college sports anymore. As a summer NY Times article explained, affluent parents are holding their kids out of kindergarten for an extra year to give them an edge.

Does a kid's relative age - whether s/he is the big frog in a relatively younger pond, or vice versa - affect his or her long-term outcomes?

To provide insight into this question, economists Liz Cascio and Diane Whitmore Schanzenbach took advantage of the fact that kids of the same biological age were randomly assigned to classrooms via the Tennessee STAR class size experiment. As always, some kids were relatively older (or younger) than their peers. But the advantage of the STAR data is that we can be reasonably sure that parents weren't pulling strings to be sure their kid was among the eldest.

On average, relative age didn't have any effect on a key long-term outcome for kids - taking the ACT/SAT. But disadvantaged kids lost out when they were relatively younger than their peers. Free-lunch recipients who ranked among the youngest 25 percent in their kindergarten classrooms were 8.4 percentage points less likely to take the ACT or SAT.

But this doesn't mean that poor kids would be better off if they started school later. Cascio and Schanzenbach also found that the effect of absolute (biological) age varied by socioeconomic status, writing, "Disadvantaged children who are older at the start of kindergarten are less likely to take the SAT or ACT, while the opposite may be true for children from more advantaged families." They attribute poor kids' disadvantage here to the fact that advantaged parents are able to provide their kids with learning opportunities not unlike kindergarten in these extra years - either at home or in a formal setting.

The policy implications? They summed up:

These findings suggest that efforts to provide disadvantaged children with higher-quality care and education prior to kindergarten, as well as changes to state and local rules governing the age of the youngest kindergartner, could substantially affect socioeconomic gaps in educational attainment.

You can find the paper here.