A new study of more than 100,000 New South Wales primary school students has found that one-in-four families delay their child’s school entry until the year they turn six.

Associate Professor Ben Edwards from the Australian National University co-authored the study.

He told Tom Elliott that boys, and children from more affluent families, are more likely to be delayed in starting school.

“Those who are from less affluent families, or from families who don’t speak English at home, are more likely to go on time,” he said.

Professor Edwards said there is a similar phenomenon in Victoria, but not to the same degree, with earlier research indicating about one-in-ten Victorian kids are delayed in starting school.

Holding children down a year is now much rarer that it used to be.

“If kids are held back they’ll be held back in the year before they start school… primarily because the social cost associated with being held back is potentially quite high,” Professor Edwards said.