Police exert tremendous power at the gateway to all criminal justice systems: they determine who enters and how. It is therefore not surprising that the disproportionate rate of apprehension amongst Aborigines is often cited as evidence of police discrimination. Yet in Australia, little empirical research has as yet been conducted on the specific question of racial bias in the exercise of police discretion. Although the issue of poor relations between Aborigines and police has often been raised, no studies have attempted to assess systematically police behaviour at the point of apprehension. Under what circumstances do police apprehend Aborigines? What determines the nature and number of charges laid, and why do they choose to arrest rather than report so many Aborigines?

The lack of research in this area is of major concern, since arguably, the most crucial decision taken in the whole criminal justice system is the decision that an individual should enter it. Once a person is brought within the formal process, the real costs can be considerable, even if the final outcome entails no conviction or sentence. The police take a decision at the point of apprehension which sets in motion a mechanism which may be slow and frustrating, and which may have a considerable impact on an individual's life, even if he or she is subsequently exonerated.

An extreme illustration of the possible cost to the individual of participation in the judicial process is dramatically provided by the current debate surrounding Aboriginal deaths in custody.