below). Others argue that most drug arrests are not only in response to drug use, per se, but also to other types of illegal drug-related activity and that these arrests generate a large proportion of drug possession arrests. They also argue that blacks selling drugs tend more often to operate in street markets, whereas whites tend to operate more surreptitiously; hence the difference in arrest rates may be attributable to different vulnerability to arrest rather than to racial bias in the arrest process.

A similar argument arises over the difference between the black arrest percentage (37 percent) and the black prison percentage (56 percent). Some argue that these data show that the post-arrest operation of the criminal justice system is biased against blacks. They cite the 100:1 disparity in the federal sentencing rules for crack (predominantly sold by blacks) compared to powder cocaine (much more often sold by whites) as an indication of that bias. A counter-argument is that crack use and crack markets are much more often accompanied by violence, which warrants more severe treatment in the criminal justice system. In addition, it has been argued that the race of convicted drug offenders may be correlated with other factors, such as prior record, that can account for the differences in sentence severity.

These polar views, as well as intermediate hypotheses, can co-exist because we lack the data and research necessary to resolve the controversy. Perhaps the most basic problem is that we lack data on offense rates by racial/ethnic groups. It is clear that use prevalence rates do not vary substantially among racial and ethnic groups. Based on the 1998 NHSDA data, it has been estimated that 74.3 percent of all current (past 30 day) illegal drug users are white, 15.4 percent are black, and 10.3 percent are Hispanic, substantially equivalent to their proportions of the adult population. For cocaine, in particular, 64.8 percent of 30-day users were white, 18 percent were black and 16.9 percent were Hispanic. However, these basic prevalence figures do not tell the whole story because frequency of use (and therefore the real rate of offending) among various population groups is unknown. Most importantly, household surveys miss the heaviest users. Finally, rates of trafficking are unknown. In the absence of data about rates of offending, the available information on contacts with the criminal justice systems is consistent with multiple interpretations.

These issues are clearly complicated, and a simple comparison of race-specific ratios at different parts of the criminal justice system cannot prove bias, although they do prompt a search for a clearer explanation of the reasons for the difference. Until those explanations arrive, it is likely that concern about the possibility of bias will continue. Thus, it is important that research be directed at tine factors that can explain the significant