A university degree is supposed to be a student's meal ticket, a guarantee of future prosperity. But new research suggests the wage gap between a high school certificate and a bachelor's degree is shrinking.

Laura Baxter studied for nine years to become a teacher. Credit:Chris Hopkins

Those with bachelor degrees still make more money than classmates who only have Year 12 certificates, but the university wage advantage has deteriorated over the past decade.

Male university graduates at the start of their careers were earning less in 2016 than they would have a decade ago, according to a new Grattan Institute report tracking post-tertiary incomes.

In 2016, the average early-career salary for a man with a bachelor's degree was 54,348, which was $1,410 less than he would have earned as a graduate in 2006, when he would have commanded $55,767.