I don't have a link, but there was a comparative study done on children in Norway during the debate on lowering school starting age (it was 7 years when I was at school - it's 6 years now, and there's some pressure to lower it to 5).
They compared salaries and other factors based on age at school start and found basically no statistically significant differences later in life between those who had been oldest and youngest when starting school.
They did not look at things like health or stress levels, though.
They compared salaries and other factors based on age at school start and found basically no statistically significant differences later in life between those who had been oldest and youngest when starting school.
They did not look at things like health or stress levels, though.