School principals are getting older - and one in every eight are now quitting or moving schools each year.
A first-time study of principal turnover by the Ministry of Education has found that the number of principals quitting or switching schools dropped sharply in the global financial crisis, but has since crept up again to 15 per cent in 2017 and 12 per cent in 2018.
"Of the principals leading schools in 2018, 88 per cent were leading the same school in 2019," the study says.
"To put it another way, roughly one in eight schools saw a change of leadership in 2019."
It says the main reason for rising turnover since 2010 is that principals are getting older, in line with all teachers.
State and integrated school principals aged 65 and over have jumped from 3.9 per cent in 2010 to 9.6 per cent in 2019.
Consequently the numbers aged 60 and over retiring each year have grown from 60 in 2010 to more than 110 in 2018.
Robin Staples, who retired as principal of Auckland's Southern Cross Campus in April aged 69, said he committed to serve at least 10 years when he moved to the school 13 years ago after serving 10 years before that as head of Hillary College.
"I have always found in schools that you need to do a sizeable amount of time to make a difference," he said.
But he decided at the start of this year, before the Covid-19 crisis, that it was time to step down.
"I didn't want to be a principal when I was 70," he said. "In some of the higher-decile schools that might be okay, but I think particularly in decile 1 you need high energy."
In contrast, principals quitting under age 60 and not moving to another principal's role plunged from 160-180 a year from 2004-2007 to just over 100 in 2009, and have stayed around 100 a year ever since.
The numbers switching schools also declined in primary schools, from 6 per cent in 2004 to 3 per cent since 2008, and remained about 2 per cent a year in secondary schools.
Principals have become slightly more likely to be non-European - Māori up from 12.6 per cent of principals in 2010 to 17.1 per cent in 2019, Pasifika up from 1.2 per cent to 2.4 per cent, and Asians up from 0.5 per cent to 0.8 per cent.
The proportion of Māori principals (17 per cent) is actually higher than the proportion of Māori teachers (13 per cent), partly because Maori-language schools tend to be small.
But principals from all minority groups are still under-represented compared with domestic school students, who are 24.5 per cent Māori, 13.5 per cent Asian and 9.9 per cent Pasifika.
Women now make up 57 per cent of primary principals, up from 44 per cent in 2005, and 37 per cent of secondary principals, up from 31 per cent.
Rototuna Senior High School principal Natasha Hemara, who is moving next term to lead Kamo High School, said no one has "targeted" the demographics of principals to achieve a better match with students.
She hopes that a new leadership centre planned within the Teaching Council will focus on the issue.