Projecting the proportion of women in trades
Key findings

With the release of research findings for the Women in Trades project, BCITO set an ambitious target for the construction sector: “By 2040 to have 30% of construction trade roles filled by women”. We use our Inchworm model to simulate how this can be achieved, and what this means in terms of the number of women that need to be attracted into the sector.

For the best case scenario, we limit our approach to the construction industry that we found to have the most success in attracting women: painting and decorating. Over the past 10 years, the painting and decorating sector has increased the proportion of women working in their workforce from 5% to 10%. A back of the envelope calculation would suggest that you would need to displace another 20% of the workforce with women. With a workforce size of 13,000, recruiting 2,600 new women painters sounds achievable at just 130 a year by 2040. However, this calculation fails to account the need to replace existing painters who will leave the industry, growth within the industry, and retention rates of new painters. Only about 50% of new painters in 2013 are still working in the industry after one year. Inchworm is an agent-based model that simulates a workforce down to the individual worker. The model allows us to incorporate data we have on the retention rates, role structures, and training volumes.

If we assume that the growth in attracting women is exponential, that more women entering the industry will have a compounding effect of attracting other women, our model calculates that, year on year, the number of women entering the sector needs to increase by 5%. At first, in 2020 this is achievable at 260 women painters, but that number quickly grows. By 2040 the number of women entering the painting and decorating industry needs to almost match parity with number of new male painters, at 960 new women painters. In total, over the next 20 years the painting and decorating industry will need to recruit 11,800 new women to achieve this target.


Access to the data used in this study was provided by Stats NZ under conditions designed to give effect to the security and confidentiality provisions of the Data and Statistics Act 2022. The results presented in this study are the work of the author, not Stats NZ or individual data suppliers.

These results are not official statistics. They have been created for research purposes from the Integrated Data Infrastructure (IDI) which is carefully managed by Stats NZ. For more information about the IDI please visit

The results are based in part on tax data supplied by Inland Revenue to Stats NZ under the Tax Administration Act 1994 for statistical purposes. Any discussion of data limitations or weaknesses is in the context of using the IDI for statistical purposes, and is not related to the data's ability to support Inland Revenue's core operational requirements.