The ethnic disparities discussed above, either singly or in combination, are unlikely to be sufficiently large to account for the scale of over-representation of Māori in the criminal justice system. Were Māori on average no more or less likely to engage in criminal behaviour than their fellow (non-Māori) citizens, the degree of bias operating in criminal justice processes would have to be on an extraordinary scale. The following section of this report will examine the evidence for the notion that Māori over-representation in criminal justice statistics results from disproportionately high exposure to early influences and social-economic factors which in turn raise the risk of later involvement in criminal activity.
The approach taken in exploring this explanation may be summarised as follows: a great deal of research evidence supports the conclusion that children who experience certain types of developmental circumstances during childhood, or display certain behavioural characteristics, are at higher risk of going on to behave criminally during adolescence and adulthood. It is of interest therefore to review evidence which reveals the extent of differences in such characteristics when analysed by ethnicity. If over-representation of Māori children in these at-risk sub-groups is similar in scale to that which is found in current criminal justice statistics, then it might reasonably be inferred that the latter is related to the former.