In the years after graduation, the annual earnings of men steadily outpace those for women, even within fields that have the highest numbers of women graduates.

The graph below shows the gaps between the median annual earnings of men and women in the most popular fields of study for women graduates – fifteen subjects ranging from biological sciences to education, business, arts and humanities.

These figures are historical and come from a different data source than the other data used in What’s My Gender Pay Gap. The data here uses median annual earnings instead of median hourly earnings. This means the data doesn’t account for differences in the number of hours men and women work. This is significant because 1 in 3 New Zealand women over 30 work part-time; most men and women under 30 work equivalent hours.

Nevertheless these graphs show a clear trend across virtually every field of study: pay differences begin low, often at zero (or in some cases even a pay gap in favour of women). But by nine years after graduation each field of study shows a gap in graduate earnings in favour of men, and in some fields this gap rises to over 25 percent.

Gender Pay Gap Between Men and Women with the Same Qualifications (by year after graduation)

Gender Pay Gap Between Men and Women with the Same Qualifications (by year after graduation)

There are several factors underlying this trend. As shown in our report for Age Groups, the gender pay gap widens over time because younger people (including new graduates) tend to earn less; the closer you are to minimum wage, the closer you are to wage parity. With more experience and higher wages, the gap widens. Research has shown that the higher the discretion in setting wages, the higher the gender pay gap.

For many people, five to nine years after graduation is around the time they become parents – and many women of this age will have moved into roles as primary caregivers of children. These women are much more likely to be working part-time than men, devoting unpaid hours to caring. In many lines of work reduced hours result in slower, or even backwards, career progression. We call this the “Motherhood Penalty”, and you can read more about it here.

Recent studies have investigated the GPG in highly-educated sectors. You can read about pay gaps for medical professionals here, and about pay gaps between academic researchers here.