Women who attended single-sex schools are less likely to be victims of New Zealand's growing gender pay gap, a professor claims.
International research has shown that women who went to all-girl schools are more competitive than their counterparts.
Co-ed students are less likely to negotiate their salaries face-to-face as they enter the workforce and the problem becomes more pronounced throughout their careers, creating the gap.
Professor Ananish Chaudhuri of the University of Auckland has looked into studies from around the world on the issue. "The existence of a gender gap in the workplace is well documented, along with some of the reasons why - motherhood penalties and the like," he said.
"However, when comprehensive studies take into account the large number of variables - such as education, age, labour market experience, race, time in the workforce, time spent in childcare, discrimination, average hours worked, college grades and choice of occupation - there is still a substantial part of the gender wage gap that remains unexplained - in fact, up to one-third of it.
"And recent research comparing the behaviour of women who went to single-sex versus mixed-sex schools has found that women from all-girl schools are as competitive as men, while those educated alongside boys are less so.
"This obviously has implications for the nature of schooling that we provide our children."
The behaviour of 260 students of both sexes was compared in a joint study between the Australian National University and Essex University in England.
They were asked to enter a competition that included a small financial reward.
Girls from single-sex schools and boys from both single-sex and co-ed schools were equally likely to behave competitively in the experiment.
Girls from co-ed schools were much less likely to participate, but the likelihood of girls participating rose after they were placed in single-sex groups.
New Zealand's current gender salary gap is 9.6 per cent, but is much higher for several professions, including accountancy, which has a 26 per per cent gap.
Some of the country's most powerful women went to single-sex schools, including former Prime Ministers Helen Clark and Jenny Shipley. Others include former Telecom chief executive Theresa Gattung, Slingshot founder Annette Presley and former Westpac NZ chief executive Ann Sherry.
Alison Gernhoefer, who was principal of Westlake Girls' High School for 30 years until the end of last year, said girls could avoid "the glass ceiling" at single-sex schools.
She attended an all-girls school and had also taught at co-ed schools.
"When producing a play, in my experience, the boys used to love doing the lighting and things like that. In a single-sex school, girls have to accept that responsibility and they do it very well. They've possibly not thought that they could do it.
"The sky's the limit ... The boys just like doing those things and some girls stand back and let them."
Undistracted by boys
Powerful Kiwi women who went to all-girls schools:
Helen Clark former Prime Minister - Epsom Girls' Grammar School.
Theresa Gattung former Chief executive of Telecom - McKillop College, Rotorua.
Annette Presley founder of Slingshot - McAuley High School, Otahuhu.
Ann Sherry former Westpac NZ chief executive - Somerville House, Brisbane.
Dame Jenny Shipley former Prime Minister - Marlborough Girls' College, Blenheim.
Hekia Parata Education Minister - Gisborne Girls' High School.
Maryan Street Labour MP - New Plymouth Girls' High School.
Jo Goodhew Women's Affairs Minister - Timaru Girls' High School.
Anna Paquin Oscar winner - Wellington Girls' College.
Samantha Harrison Black Sticks midfielder - Diocesan School for Girls.