Answer: Disproportionate black imprisonment results from the interplay of multiple factors. These likely include disproportionate involvement in crime, particularly violent crime; policing practices in predominantly African American neighborhoods; disparate treatment in the court and corrections systems; and harsh sentencing laws that disproportionately affect black defendants.

The Facts: The American criminal justice system has been marked by stark racial disparities for at least a century and half. Most horrific was likely the use of a vicious and transparently biased “justice” system by southern whites after the Civil War in order to force the newly freed blacks into conditions of bondage that closely resembled slavery ( Oshinsky, 1996 ). The era’s most notorious practice may have been routinely sending black convicts (and only rarely white) into chain-gang labor involving conditions of extreme (and frequently lethal) privation. Later, as the nineteenth century shifted to the twentieth, a new system of “Jim Crow” justice developed that may have been less brutal in some respects but that continued to treat black defendants unequally, especially in cases in which a black person was alleged to have assaulted or raped a white victim ( Klarman, 2009 ).

Yet, while southern justice remained notoriously racist through the middle of the twentieth century, it should also be appreciated that northern justice was hardly a model of racial enlightenment. Northern prejudice became increasingly salient as the so-called Great Migration of the early and middle decades of the twentieth century brought a flood of southern blacks into northern and western cities. Through a combination of formal and informal housing restrictions, the new arrivals found themselves crowded into segregated, run-down “ghetto” neighborhoods. Heavy-handed policing of these neighborhoods led to a series of major urban race riots in the 1960s.

During the Civil Rights Era, overtly racist laws and government practices were finally overturned across the United States, but racial disparities in the criminal justice have persisted to the present day. Thoughtful commentators now debate whether the present system is appropriately labeled “the new Jim Crow,” which would imply that contemporary mass incarceration reflects an agenda of legally enforced racial subordination reminiscent of the pre-Civil Rights South ( Alexander, 2012; Forman, 2012 ).

It has proven difficult to fully and precisely delineate the causes of disproportionate African American incarceration. Q34, for example, examined how much of the disproportionality can be explained by reference to different rates and severity of criminal activity? Based on the victim survey and arrest data, it seems reasonably clear that African Americans are disproportionately the perpetrators (and, for that matter, also disproportionately the victims) of major violent crime. At the same time, the available evidence also suggests that disproportionate black crime cannot fully account for disproportionate black incarceration. Put differently, it seems likely that differential treatment by various actors in the criminal justice system likely amplifies the impact of differential crime patterns.

Before considering more specifically how disparity arises in the criminal justice system, one further point about crime patterns should be emphasized: to say that disproportionate incarceration is caused by disproportionate crime is not to say that disproportionate incarceration is excused by disproportionate crime. In other words, even if the mass incarceration of African Americans represented a good faith, unbiased response by criminal justice officials to serious crime problems in black communities, disparate incarceration should still be regarded as a matter of public policy concern. As Q33 detailed, mass incarceration does not likely represent the most cost-effective response to crime. When it is further appreciated that mass incarceration is experienced disproportionately by individuals who live in deeply disadvantaged African American neighborhoods, such as “53206” in Milwaukee (see Q34), it becomes clear that the social costs of mass incarceration are borne largely by individuals, families, and communities that already exist in a highly precarious position—a position that to some extent reflects the legacy of generations of racial discrimination. Arguably, a due regard for this legacy creates an even greater responsibility for policy makers to implement more effective crime-control measures that impose fewer collateral costs on disadvantaged communities.

Police activity stands out as a major driver of disparate incarceration. Officers arrest African Americans at greatly disproportionate rates for serious crimes that often result in incarceration (see Q34). Moreover, the arrest disparities correspond fairly closely to the overall incarceration disparities, which suggest that the police may be the single most important institutional player in causing racial disproportionality in the criminal justice system.

Based on victimization surveys, the disproportionality in arrests for major violent crimes may very roughly mirror underlying patterns in offending. In other crime categories, disproportionate arrests are more likely to result from selective enforcement practices by the police (Q34). Page 192  |  Top of ArticleResearchers studying drug enforcement in Seattle provide a striking illustration ( Becket, Nyrop, & Pfingst, 2006 , 129-30). They found far more police activity targeting one racially diverse open-air drug market than an overwhelmingly white open-air market operating elsewhere in the city—a disparity that could not be explained based on either crime rates or citizen complaints. The researchers “were able to observe hundreds of outdoor heroin transactions in [the white] area in a fairly short period, the vast majority of which involved white users and dealers” and that seemed “largely invisible to law enforcement” (130). Even in the racially diverse drug market, interviews with police officers suggested that they paid little heed to “a significant and overwhelmingly white market for illegal prescription drugs” that operated alongside the black-dominated distribution of crack cocaine on which officers focused. The researchers concluded that there was likely an “unconscious impact of race on official perceptions of who and what constitutes Seattle’s drug problem.”

Disproportionate drug arrests are sometimes defended as “pretextual,” that is, as reflecting an appropriate, opportunistic use of drug laws as a tool to nab individuals who are suspected of violent or other serious nondrug crimes (see Q32). The defense often goes like this: if police resources are concentrated as they should be in high-crime neighborhoods, and if officers in those neighborhoods proactively stop and investigate individuals who fit a “profile” for likely involvement in nondrug crimes, then resources will be concentrated disproportionately in African American neighborhoods and the residents of those neighborhoods will be disproportionately stopped by the police, with some percentage of those stops inevitably turning up contraband (drugs or guns) and leading to an arrest. In this way, a race-neutral policing strategy that properly seeks to disrupt nondrug crime may lead to racially disparate arrest numbers for drug and gun offenses.

Yet, there remain concerns about the extent to which disproportionate arrests may reflect unfair racial biases. Consider three bodies of evidence. First, research indicates that police have a higher “hit” rate when they stop whites than blacks, that is, they are more likely to find contraband or otherwise establish a basis for making an arrest ( Harris, 2017 , 138-39). This suggests that officers tend to be less accurate when they determine that a black person may be involved in criminal activity. Second, research indicates that predominantly African American neighborhoods are stigmatized, which includes being perceived as crime-ridden without regard to the actual crime rate ( Hannon, 2017 ). Such racially biased perceptions can affect police behavior. For instance, a recent study in Philadelphia found elevated rates of police frisking pedestrians for weapons in black Page 193  |  Top of Articleneighborhoods regardless of neighborhood violent crime rate. The study also found that frisks in black neighborhoods tended to have a lower hit rate, suggesting that police were unduly quick to decide that residents of those neighborhoods might pose a threat.

Third, and finally, a quite large body of research finds that negative stereotypes about African Americans are widespread, often operating at a subconscious level ( Ghandoosh, 2014 , 13-16). The term “implicit racial bias” is used for these subconscious racial views. One set of studies makes use of the online Implicit Association Test (IAT), which draws out the negative and positive associations that people have with different groups. About 75 percent of test-takers seem to exhibit a bias in favor of whites over blacks. This sort of bias has also been found when the IAT has been administered to criminal justice professionals, including judges and even defense lawyers. Other studies have found that Americans tend to overestimate the proportion of crime committed by blacks, and to believe that blacks are more violence-prone than whites. Video-simulated shooter studies, including studies involving police officers, find that blacks are more quickly perceived to be armed and dangerous than whites.

Collectively, all of this evidence lends support to suspicions that some black neighborhoods may be unjustifiably targeted for high-intensity policing, and that many police stops of black pedestrians and motorists may be tainted by racial biases. Through such mechanisms, police bias could conceivably play a significant role in the racial disparities that exist in the arrest data, and hence also the disparities that exist in the imprisonment data.

Although prosecutors are the recipient of a racially disparate arrestee population, they may in some respects exacerbate the disparities. Particularly important are their charging and plea-bargaining decisions. There is no reason to assume that prosecutors are immune from the problems of stereotyping and implicit racial bias that seem so widespread in American society. However, the prosecutor’s role in relation to disparate incarceration has been studied much less extensively than the roles of the police and sentencing judges. Still, the available research, while limited, tends to find that race does affect charging and plea bargaining ( Committee on Causes and Consequences of High Rates of Incarceration, 2014 , 97). For instance, a recent study of court records in Madison, Wisconsin, found that white defendants were 25 percent more likely than black to have a charge dropped or reduced by the prosecutor ( Berdejo, 2018 ). Notably, this disparity did not exist in higher-level felony cases or as to defendants with prior convictions. The patterns suggest that first-time white defendants facing misdemeanor or low-level felony charges benefit Page 194  |  Top of Articlemore than their black counterparts from a presumption that the criminal conduct was aberrational and is unlikely to be repeated.

Research on the judicial role similarly finds measurable, but generally modest, contributions to incarceration disparities. Most studies focus on sentencing, although there is also some research on other judicial decisions. For instance, judges are more likely to order black defendants than white defendants jailed while awaiting trial ( Committee on Causes and Consequences of High Rates of Incarceration, 2014 , 93). This tendency is important in its own right but may have even greater significance than first appears since pretrial detention is associated with less favorable plea deals, higher conviction rates, and a greater likelihood of an incarcerative sentence.

When it comes to sentencing, much evidence suggests that black defendants tend to receive harsher punishment than whites. For instance, in federal court, sentences are on average nine months longer for black than white males ( Schmitt, Reedt, & Blackwell, 2017 , 3). Nationally, blacks account for more than 48 percent of life-sentenced prisoners ( Nellis, 2017 , 15). In Florida, blacks convicted of felony drug offenses receive sentences two-thirds longer than whites ( Salman, Lee, & Braga, 2016 ). In Madison, Wisconsin, 52 percent of black defendants are sentenced to incarceration, as opposed to only 35 percent of whites ( Berdejo, 2018 ).

However, such gross comparisons do not necessarily indicate that judges are exercising their sentencing discretion in disparate ways. For one thing, some racial sentencing differences result from the application of mandatory minimums. For instance, in the federal system, more black than white drug defendants are subject to a mandatory minimum ( U.S. Sentencing Commission, 2011 , D-39). Indeed, blacks account for 54 percent of mandatory sentences of twenty years or more, and nearly two-thirds of mandatory life terms. In Florida, blacks account for two-thirds of the defendants subject to a sentence enhancement for carrying drugs in one of the protected zones around churches, parks, and housing projects ( Salman, Lee, & Braga, 2016 ). Such sentencing laws have a disproportionate impact on African Americans in other states, too; the high-density urban neighborhoods where many African Americans live tend to be blanketed by protected zones ( Ghandoosh, 2015 , 15). “Three strikes and you are out” and other recidivism-based mandatory minimums may also disproportionately affect African Americans. Meanwhile, under the Minnesota sentencing guidelines, many more black defendants are recommended for imprisonment than would be expected based only on racial differences in arrest or conviction rates ( Frase & Mitchell, 2017 ).

Yet, even apart from the impact of minimums and guidelines, there appear to be racial disparities in sentencing that cannot readily be accounted for by reference to legally permissible sentencing factors, such as offense severity and criminal history. For instance, the U.S. Sentencing Commission has concluded that on average black male defendants receive sentences that are 19 percent longer than similarly situated white male defendants ( Schmitt, Reedt, & Blackwell, 2017 , 2). Dozens of other studies on federal and state sentencing systems find similar results ( Spohn, 2017 ). Controlling for a range of different variables, blacks are in general more likely than whites to be sentenced to incarceration, and when incarcerated to receive longer terms behind bars. It is not clear why race has this impact, but it seems quite plausible that implicit racial bias plays a role, as well as some aspects of African American socioeconomic disadvantage that are not controlled for in the research.

Similar factors may also affect decision making at the “back end” of the criminal justice system. While racial disparities in corrections and parole have not been studied as much as disparities at the sentencing stage, some studies do find that black offenders tend to receive less favorable outcomes as to, for instance, discretionary parole release from prison and revocations of community supervision ( Huebner & Bynum, 2008; Steinmetz & Anderson, 2015 ).

In sum, while African Americans are already dramatically overrepresented relative to their share of the general population at the very first (arrest) stage of the criminal process, racial disparities are likely amplified at later stages from charging and pretrial release through parole release and community supervision. Moreover, it does not appear that disparate outcomes in the court and corrections systems can be entirely accounted for by reference to offense severity or criminal history. However, in appropriately controlled studies, the unexplained racial disparities are not necessarily large at any given stage of the process and are often confined to particular offense categories. Yet, as a committee of the National Research Council recently concluded, the “cumulative effect [of modest unwarranted disparities at each stage] is significant” ( Committee on Causes and Consequences of High Rates of Incarceration, 2014 , 93).