5.1 Inter-group movement

Although the estimate for the effect of father's SES is a valuable summary statistic, we lose considerable detail about how mobility varies between occupational groups (Blanden, et al., 2004, p. 140). We will now therefore examine intergenerational movement between four broad occupational groups.[30] The estimates in Table 5 indicate that people from lower New Zealand Socio-Economic Index (NZSEI) occupational groups tended, on average, to be more intergenerationally mobile than people from higher income occupational groups. The diagonal (in bold) shows estimates of the proportion of those on the electoral roll (aged 25 years or older) who were in the same NZSEI occupational group as their father. The results imply a relatively high degree of intergenerational mobility for those whose fathers were in the lowest two NZSEI occupational groups: only 31.7% and 27.5% respectively of people from these groups were in the same occupational group as their father. In contrast, the percentages that were in the same occupational group as their father were 35.6% and 41.6% for the second-highest and highest groups respectively. Those born into families in the top two quartiles seem less likely to be downwardly mobile than those in the bottom two quartiles seem likely to be upwardly mobile. A Chi-test confirms differences in patterns of inter-quartile movement between those who grew up in families in the top two quartiles and those who grew up in families in the bottom two quartiles.

These estimates are similar to those found using 1993 Election Study data, and suggest that the relationship between the occupation of people and that of their father is not perfectly linear. We also tested whether the relationship between father’s SES and the SES of their children was a polynomial. For men, the term for the square of father’s SES was not statistically significant even at a 10% level. For women, the square was statistically significant, but negative. There is therefore some evidence that the relationship between father’s SES and the SES of their daughters is not consistent across the distribution of SES. However, adding a locally weighted regression line to a scatter plot of the SES data (see Section 8.2.4) indicated that this is a relatively small deviation. Similarly, although the point estimates for quartile regressions differed, the confidence intervals for these estimates overlapped.

The average SES for fathers in Table 5 was 39.9 and the average SES for their children was 40.8. This suggests only slight upward occupational mobility by New Zealand's entire population over time. As the results have already indicated, there is a statistically significant gender difference between the SES of children, with males 25 years or over having an average SES of 42.7 and females in this age group having an average SES of 39. The biggest difference between the occupations of fathers and of their children is that considerably fewer children work in agriculture and farming. In total, 19.3% of the fathers of people aged 25 or older worked in agriculture and farming. In contrast, 7.9% of their children aged 25 years or older (10% of males and 5.9% of females) worked in agriculture and farming. Although in the NZSEI framework different types of farmers have different scores, most farmers receive the lowest SES score in the second highest occupational group (Galbraith, et al., 2003).

Source: Author's calculations based on 1996 NZES and quartile boundaries used in the New Zealand Socio-Economic Index Users' Guide. Because the distribution of SES implied by the Election Study data differs from the distribution used to construct the quartiles, there are more sons, daughters and fathers in some of these groups than in other groups.