To conduct this analysis, 11 cohorts of 19 year old New Zealand residents that were enrolled in training institutions at age 19 from the Ministry of Education records. Each cohort is classified based on the year that they turned 19. These cohorts were then categorised based on the highest qualification the individual had obtained by age 25. Using IRD records the median incomes for each cohort was calculated based on the category they were in and tracked over time.
The categories include university, trade apprentices, other ITOs, ITP (Institute of Technology and Polytechnique), and no training. We broke up the Industry Training Organisations (ITOs) into two categories, trade apprentices and other ITOs. The trade apprentices comes from the trade related ITOs such as BCITO, Competenz, Skills Org, Connexis and MITO.
If a person moved overseas and had no income in that year they would be excluded from the calculation of the median, as they would not have active IRD tax records. Income is calculated from wages, salaries and business income sources. Beneficiary income and rental incomes are excluded.