4  Poor outcomes: Causes and contributors

While the previous section reviewed the way child development can affect later well-being, this section explores the principal influences that affect child and adult outcomes. These influences include individual, family and community factors.

Outcomes in adulthood reflect a complex interplay of genetic and environmental factors over a person’s life course. Genetic factors can contribute to susceptibility to negative outcomes. Inherited characteristics seem to be particularly important in physical and cognitive development, aspects of personality, and some forms of mental illness. The influence of genetic factors tends to increase as individuals get older, relative to peer and family influences.

A relatively small proportion of the variation in adult outcomes is attributable to differences in the home environment. Nevertheless, “within-home” family factors do have a significant developmental effect. Although it is not clear how neighbourhoods affect children, it is likely that any effect operates through resources, norms and the social networks available to parents. A relatively small, yet economically significant proportion of the variation in individual outcomes is attributable to differences in the characteristics of schools.

A large part of individual variation in outcomes, however, remains unexplained. There is no single theory of the determinants of well-being, and simple responses to adverse outcomes are not likely to be effective. A number of domains are likely relevant to understanding the determinants of particular outcomes of interest, and this needs to be taken into account in policy design.

The determinants of good and bad outcomes in adulthood from a life-course perspective are multiple, complex and inter-related. No single set of factors has an over-riding influence on any one outcome. Yet it is useful to be able to identify the nature and relative importance of different influences through time to understand the potential effects of interventions intended to ameliorate or prevent adverse outcomes.

4.1  Individual influences

Genetic factors are important in a wide range of child outcomes, particularly IQ and verbal ability, that affect later outcomes. Between 25% and 55% of many cognitive abilities seem to be heritable. This suggests an appreciable variation adult outcomes is inherent.

The relative effect of inheritance is masked for most children by the pervasive influence of family influences in early childhood (Plomin and Petrill 1997). Also, inherited characteristics can influence the environments in which people grow up and vice versa, and thus affect adult outcomes (Burgess, Gardiner and Propper 2001, Masten 1994). For example, personality appears to have a strong heritable component that leads individuals to take part in different activities and mix with different sorts of people, thereby developing different life skills.

Much evidence points to the fact that children from ethnic minorities have poorer outcomes than the dominant ethnic group in many societies – though this is by no means universal, since children from some ethnic minority groups have better outcomes than their peers. In New Zealand, young people of Maori and Pacific Island descent have poorer health and education outcomes in both childhood and adulthood than their European counterparts (Treasury 2001b).

It is not clear whether the link between ethnicity and outcomes is causal or correlational: does ethnicity itself have an effect on child and adult outcomes, or do these outcomes result from other factors that are associated with ethnicity, such as income, family structure, level of parental education, or neighbourhood disadvantage? This distinction is important because it may help identify the relative importance of particular causal mechanisms that need to be addressed through interventions.

Overall, once other factors have been taken into account (age, marital status, industry and occupation, education and literacy), research suggests that the effect of ethnicity on outcomes such as earnings (measured in terms of differences in means) is usually much reduced (Alexander, Genc and Jaforullah 2000, Gibson 2000, Maani 2000a, 2002).[15] Nevertheless, the remaining effect may be both statistically and economically significant, and it is useful to gauge its importance relative to the effect of other factors.

In seeking to understand the effect of ethnicity on outcomes, it is important to understand the mechanisms through which it may cause disparities in the outcomes of children from different ethnic groups. For example, there is strong evidence that average literacy and numeracy levels of Maori and Pacific adults are lower than those for the rest of the population, even for people in similar occupations, and that this affects employment and earnings outcomes (Chapple 2000, Maré and Chapple 1999, Nash 1997). There is also evidence that this affects the ability of families to support their children’s education in the home (Nash 1997). It is precisely in the areas of literacy and numeracy that the disparity between Maori and Pacific children and others is widest in primary schools (Crooks and Caygill 1999). Finally, there is growing evidence that these differences are important causes of disparities in adulthood (Boozer and Maloney 2001). Higher rates of lone parenting amongst Maori, entailing on average lower household incomes and resources of time, may also play a role in Maori children’s poorer educational outcomes. Higher rates of lone parenting, in turn, may be partly due to lower earnings capacity on average amongst Maori adults, as there is evidence that earnings capacity is a determinant of couple formation (Ermisch and Wright 1996). For Pacific peoples, recent migration and poor education levels are associated with poorer employment outcomes.

It is likely that these patterns hold for most other major outcomes of concern. While ethnicity may provide a “marker” for the risk of poor outcomes, other mechanisms, which are amenable to change, can provide a focus for intervention.