Careers NZ has an excellent tool that draws on the reports produced by the Ministry of Education of what graduates earn in labour market incomes after completing their qualifications.
The tool is available on the Careers NZ website and enables you to compare different levels of study with median earnings for people who studied that qualification and obtained a job.
How much income inequality is driven by poor study choices at age 18? How much of a role do qualifications actually play as opposed to actual job performance? How can an academic talk about human capital when there clearly isn’t a return on investment for many young people? All interesting stuff, and more important to have serious debate about than humdrum political noise.