A new US study has provided further evidence that being the youngest in a class can have a detrimental effect on children’s educational and social development.

The study of 528 Missouri children who were in the fifth grade (Years 56) in 1994-95 has shown that the youngest boys find it particularly difficult to keep up with their older classmates.

The researchers, Jack Jensen, an elementary school principal, and Richard Hatley, of the University of Missouri-Columbia, compared the children’s age of entry with their second and fifth-grade maths and reading scores. They also questioned teachers about the children’s social development and collected data on those who had been obliged to repeat a year.

“Our study suggests that children who are chronologically older when they enter kindergarten exhibit higher levels on multiple measures of academic achievement and in their socialemotional development than their younger peers as they progress through elementary school,” Jensen and Hatley told the AERA conference.

“The differences are more pronounced in reading than in maths and although the differences on some performance variables become less pronounced over time . . . on other key variables they persist or become more pronounced.”

Jensen and Hatley are particularly concerned about the problems experienced by some of the youngest boys who were far more likely to be asked to repeat a year than the youngest girls were.

The researchers intend to track the children’s social development and test scores as they pass through middle school and high school to see how long the effects of entry age persist. Their longitudinal analyses, they say, will help to test an assertion made by some primary teachers: “Students don’t drop out of high school, they drop out of kindergarten: they just wait several years to leave school.”