The main limitation of the census data is that it is only available for a single point in time in 2013. Although data from the 2018 census will eventually become available, we also need a way to track the number of women on an ongoing basis. We can do this using tax records from the IRD.
Each employee and employer is linked to a business in a particular industry, so we can determine how many people are working in a particular industry each quarter. We do not have information on peoples' occupation, however, so we cannot refine our analysis to only tradespeople. The IRD data will include workers of all occupations in the workforce for each sector. Since a large proportion of administration staff are female, the proportion of women is greater than in the census data.
In general, we see an increase in the size of the workforce over time, with decreases in the years following the recession. Looking at employees only, the trend in the proportion of women varies between sectors. For example, Painting and Decorating has had a strong increase in the proportion of women, while the proportion of women in Cement and Concrete has been flat.
If we look at employers and self-employed workers, an important point to note is that the data for the 2017 tax year are incomplete, so we can only consider the data up to the first quarter of 2016. The trend in the proportion of women among employers is mostly negative, even in sectors where the proportion among employees is increasing. What might be the explanation for this? The proportion of employers who are female is higher than employees, whereas in the census data these proportions are similar. Many of these additional female employers are likely to be partners and spouses of tradespeople receiving income from a jointly owned business. The decrease in the proportion of female employers may result from changes in the way businesses are structured or even changes in marriage rates. For this reason, it is more meaningful to look only at employees when tracking changes in the proportion of women.
When you hover over the chart, arrow buttons will appear in the top-left. You can use these buttons to switch between yearly and quarterly views of the data.