Women earned 7 percent less than men on average – whether they worked for a man or a woman and regardless of the share of women managers in the organisation

Women are just as likely to earn less than men when they work under a female supervisor or in a company with a high proportion of women at the top, academics said on Thursday.

Simply hiring more women into senior posts did not appear to be a solution to persistent wage inequalities, they concluded in a study published in the European Sociological Review.

The findings suggest female mangers may struggle to challenge organisational structures that favour men, said the paper’s lead author Margriet van Hek, a post-doctoral researcher at Radboud University in the Netherlands.

“They often are a minority and they kind of have to show they have really earned their place by not showing female solidarity,” she told the Thomson Reuters Foundation.

“They have to show they are the right man for the job, so as to say, by behaving extra masculine.”

The study compared data covering nearly 8,000 men and women at 231 organisations across nine countries from the European Sustainable Workforce Survey, a scientific research project.

The employees worked in manufacturing, healthcare, higher education, transport, financial services and telecommunication.

Researchers found a “considerable and significant gender gap”, with women earning 7 percent less than men on average – whether they worked for a man or a woman and regardless of the share of women managers in the organisation.

That is a smaller pay gap than other studies have found.

Data from Eurostat, the statistical office of the European Union, shows women on average earned 16 percent less per hour than men across the bloc in 2017.

Hek said she had been surprised by the results, as the team had expected that women might benefit from female management.

Instead, businesses must take action to ensure all workers are treated equally, irrespective of gender, said Serena Fong of Catalyst, a global nonprofit promoting women’s rights at work.

“The gender wage gap will only be eliminated when organisations put policies in place that create more gender-inclusive workplaces,” said Fong, citing pay transparency, salary setting and recruitment procedures as focus areas.

Gender inequality in the workplace could cost the world more than $160 trillion in lost earnings, the World Bank says.