Delaying Kindergarten – the impact on mental health

Delaying a child's enrolment to Kindergarten for a year has mental health benefits, according to new research from Stanford University.

The study was based on a large-scale survey tracking Danish children that included the collection of mental health data for seven and 11 year olds. It found a one year delay reduced inattention and hyperactivity by 73 per cent for an average child.

In education psychology, inattention and hyperactivity is closely associated with self-regulation – the ability to monitor and control behaviour and focus on a goal, which researchers have linked to student success.

A growing number of parents in developed countries are choosing to delay their child's enrolment in formal schooling. ‘Historically, US children attended Kindergarten as five-year-olds and First Grade as six-year-olds. However, roughly 20 percent of kindergarten students are now six years old,' the Stanford study notes. In Denmark, 20 per cent of boys and 10 per cent of girls have a delayed school start.

Despite this increasingly common practice, there has been little evidence that delaying formal schooling improves educational or economic outcomes. Professor Thomas Dee, from Stanford's Graduate School of Education, and co-author Hans Henrik Sievertsen, of the Danish National Centre for Social Research, focused their research on mental health benefits.

‘Our results indicate that a one-year increase in the school starting age leads to significantly improved mental health,' the authors report.

More importantly, they say, the effects persisted when children were aged 11, but add ‘… the estimated effects of school starting age on other mental health constructs, which have weaker links to subsequent student achievement, are smaller and less persistent.'

Dee and Sievertsen based their study on the Danish National Birth Cohort (DNBC), which includes data from a widely used mental health screening tool, specifically designed for children and teenagers called the Strengths and Difficulties Questionnaire (SDQ).

Inattention and hyperactivity is just one of the mental health constructs covered, the others are emotional symptoms, conduct problems, peer problems and a prosocial behaviour scale.

In Denmark, Kindergarten is called Grade Zero and begins in August of the year in which the child turns six. The researchers were able to use this rule to examine the impact of a delayed school start time, by comparing data for children who were born on 1 January, and those born on 31 December the previous year.

Prior to starting formal schooling, more than 95 per cent of children attend daycare. ‘So, children who are born on 1 January and who comply with the rules will have a school starting age that is one year higher (and one extra year of daycare) relative to the children born just one day earlier,' Dee and Sievertsen explain.

They say the fact the mental health benefits were narrowly confined to inattention and hyperactivity ties in with one theory of why delayed school starts may be beneficial.

‘Specifically, a literature in developmental psychology emphasises the importance of pretend play in the development of children's emotional and intellectual self-regulation. Children who delay their school starting age may have an extended (and appropriately timed) exposure to such playful environments.'

The researchers say it then becomes a question of not just when you start school, but of the pedagogical approach taken in the first year of schooling. They say further research is needed to inform effective programs and policies.


Dee, T., & Sievertsen, H.H. (2015). The Gift of Time? School Starting Age and Mental Health (CEPA Working Paper No.15-08). Retrieved from Stanford Center for Education Policy Analysis:

A working paper of The Gift of Time? School Starting Age and Mental Health is available for download at the Stanford Centre for Education Policy Analysis website. To view the paper, simply click the link.