5.5  Interacting three-way split in youth ethnicity with other covariates

Results from the short and long regressions estimated separately for sole and mixed Maori are reported in Table 14 (the results for non-Maori are reported in Table 11). The reason for interacting ethnicity with all other regressors is to see whether or not the estimated marginal effects vary systematically between the ethnic groups. The estimated effect of years not enrolled in education or training is significantly smaller for sole Maori (0.429) than mixed Maori (0.739) in the short regression, but the estimated parameters are not statistically different from one another in the long regression. There is no consistent evidence in these regressions that the rates of accumulation of actual work experience relative to potential work experience vary between the ethnic groups.

The birth of a child to female respondents significantly reduces accumulated work experience only among sole Maori. Note that several covariates had to be dropped from this estimation because of a lack of variation in these variables for the associated subsample (‘University degree or Diploma’ for mixed Maori, ‘Mother had University Degree’ for sole Maori and ‘Father had University Degree’ for mixed Maori). Both regression specifications were more successful at explaining the variation in work experience among sole Maori compared to mixed Maori. The R² statistics are uniformly higher for sole Maori (0.260 and 0.380) than for mixed Maori (0.180 and 0.182). The gain in explanatory power in adding family background measures is also substantially greater among sole Maori (46.2%) than mixed Maori (1.1%).

** Significantly different from zero at 1% level.

* Significantly different from zero at 10% level.

Notes: These data are taken from the 973 respondents in the CHDS who provided valid information for the purposes of this study. The dependent variable is the effective years of work experience accumulated by the individual between the ages of 16 and 21. Youth are defined as ‘Sole Maori’ if they identify Maori as their only ethnicity at age 21. Youth are defined as ‘Mixed Maori’ if they report both Maori and any other ethnicity, and had at least one parental figure claiming Maori ancestry by age 14. All other youth are considered to be ‘non-Maori’. Only the regression results for the two Maori groups are reported in this table. Standard errors are in parentheses.

5.6  Quantile Regressions: Three-Way Split in Youth Ethnicity

Figure 2 showed that many of the differences in work experience between non-Maori and both sole and mixed Maori are concentrated in the lower tails of these distributions. Only mixed Maori are less likely to have higher levels of work experience than non-Maori. Quantile regressions capture differences in work experience effects among the three ethnic groups at various points in the conditional experience distribution. These regression results are summarised in Table 15 for the three-way split in youth ethnicity. It is important to note that each column heading under the five percentile categories represents the results from two separate multiple regression models. Only the parameter estimates on the sole and mixed Maori indicator variables are reported. The results in the first row correspond to the short regression specification, where the additional covariates include those reported in the first column of Table 13. The results in the second row correspond to the long regression specification, where the additional covariates include those reported in the second column of Table 13.

** Significantly different from zero at 1% level.

* Significantly different from zero at 10% level.

Notes: These data are taken from the 973 respondents in the CHDS who provided valid information for the purposes of this study. The dependent variable is the effective years of work experience accumulated by the individual between the ages of 16 and 21. Youth are defined as ‘Sole Maori’ if they identify Maori as their only ethnicity at age 21. Youth are defined as ‘Mixed Maori’ if they report both Maori and any other ethnicity, and had at least one parental figure claiming Maori ancestry by age 14. All other youth are considered to be ‘non-Maori’. Additional covariates are included in these regressions, but these results are not reported. The other explanatory variables included in these short and long specifications are listed in Table 13. Each column under a ‘Quantile’ lists the results from two separate regressions estimated in STATA. Standard errors are in parentheses.

Among all the estimated coefficients on the Maori indicator variables, only those in the short regression for mixed Maori at the 0.10 and 0.50 quantiles are significantly different from zero. Once we control only for personal characteristics, ethnic differences in the accumulation of work experience appear to be concentrated in the bottom half of the distribution between mixed Maori and non-Maori. However, when we control for both personal characteristics and family background factors, these disparities between mixed Maori and non-Maori in the lower part of the distribution disappear. It again appears that our measures of family backgrounds capture at least some of the ethnic differences in the accumulation of work experience at the lower levels.