Waiting for kindergarten

The New York Times Magazine has a long survey about the practice of "redshirting", waiting an extra year to enroll children (usually boys) in Kindergarten. The article is mostly sympathetic to the idea, pointing out that many states are considering legislation to delay the cutoff date when kids must go to school.  Some takeaways:

• Cutoff dates range from Indiana (July 1) to  Connecticut (January 1).
• "Delayed-entry" children make up 6-9% of all kindergartners, a ratio that has stayed constant since records started in the 1980s.
• Finland children don't start kindegarten until age 7.
• In wealthy communities, the ratio is much higher: 25% in Los Altos, California for example.
• What do the studies show?
• A 2002 review by Deborah Stipek at Stanford found more behavior problems and few learning advantages for delayed kids.
• Labor economists think "relative age" is more important than absolute age.  A June 2005 study in Journal of Sport Sciences (and cited frequently by Freakonomics) found a disproportionate number of pro soccer players born in Jan-March.
• The biggest study is by Kelly Bedard, a labor economist at UC Santa Barbara:  Nov 2006 “The Persistence of Early Childhood Maturity: International Evidence of Long-Run Age Effects” in The Quarterly Journal of Economics. Of 250K students in 19 countries, it found a 2-11% advantage for kids who are older relative to their peers.
• Note that private schools generally have later cut-offs than public schools, a hint that competition forces schools to encourage later admission.

Bottom line: sending kids to kindergarten early seems to help disadvantaged kids by pushing them into a more professional and structured environment than they have at home, but in healthy families and communities it's better to have your kid be the oldest than the youngest in a class.