In 2007, over 7.3 million people in the United States were under some form of correctional supervision, including federal and state prison inmates (1.6 million), jail inmates (almost 800,000), those on probation (over 4 million), and those on parole (about 800,000). This means that 1 in every 31 adults in the United States is under some form of correctional control. The increase in the incarcerated population in the past three decades has been astonishing. From 1980 to 2008, the number of prison inmates (in federal and state facilities combined) increased by more than 400 percent. If we focus on increases in incarceration for drug and public order offenses (which includes weapons offenses), the increases in incarceration are even greater. There is no question that the “war on drugs” and the determinate and mandatory minimum sentences that have been a part of that war have contributed significantly to the increases in prison populations in the United States in recent decades. In recent decades, criminal justice in the United States has taken a decidedly more punitive turn, evidenced by America’s penchant for incarceration as a response to crime – even nonviolent crime.
 So who sits in America’s prisons and jails? It is clear that males and people of color are over-represented in prison and jail populations, given their shares of the U.S. population. In 2008, males constituted roughly 50% of the U.S. population, but 91% of prison and jail inmates. In terms of race and ethnicity, African Americans and Hispanics are dramatically over-represented in incarcerated populations. Each group comprises approximately 12-13% of the U.S. population. But in 2008, 40% of prison and jail inmates were black, and 20% were of Hispanic origin. If we break the incarceration numbers down by gender, race and ethnicity, and take into consideration differences in the size of white, black, and Hispanic populations in the United States, we see that, compared to white men, black men are 6.6 times more likely to be in prison or in jail, and Hispanic men are 2.4 times more likely to be incarcerated. Compared to white women, black women are 3.8 times more likely to be incarcerated, and Hispanic women are 1.6 times more likely to be incarcerated.
 How do we explain this disproportionate confinement of people of color in U.S. prisons and jails? Is it because people of color are more likely to commit the kinds of crimes that result in incarceration? Or is it because of discrimination in the criminal justice system? Unfortunately, we don’t have good data on ethnicity (Hispanic origin) and involvement in offending. But we have better data on race and offending, at least for blacks and whites. These data come from three sources: (1) victimization surveys in which victims of violent crimes are asked about their assessment of the race of the perpetrator, (2) self-report surveys of offending in which individuals report the types of offenses they have committed, and (3) “official” statistics from law enforcement agencies about the characteristics of arrested persons. While we must consider the biases inherent in each of these sources, these data suggest that African Americans are over-represented among serious offenders who commit crimes such as robbery, homicide, and aggravated assault. Yet, criminological research also shows quite clearly that racial disparities in incarceration rates are not explained solely by racial differences in offending. So it is important to consider the role of discrimination in the criminal justice system in accounting for racial disparities in incarceration. A vast social science literature exists on racial discrimination at various places in the criminal justice system, including policing (e.g., racial profiling in traffic stops, arrest decisions), bail decision making, and especially sentencing.
 Racial profiling in policing is generally defined as any police-initiated action that is based on the race or ethnicity of an individual, rather than the individual’s behavior or specific information that leads police to that person. A recent survey (of almost 64,000 people in the United States) reported by the Bureau of Justice Statistics explores contacts between police and the public, and shows that, in 2005, traffic stops were the most common reason for contact between police and citizens, accounting for 41% of police-public contacts. According to this survey, white, black, and Hispanic drivers were stopped by police at similar rates. Between eight and nine percent of survey respondents in each racial or ethnic group reported being stopped by police. However, African-American drivers were less likely than whites and Hispanics to feel that police stopped them for a legitimate reason. And there were racial and ethnic differences in what happened after the traffic stop. Blacks and Hispanics were more likely than whites to be searched and to be arrested, and Hispanics were more likely than blacks and whites to be ticketed. Whites were more likely than others to be given written or verbal warnings.
 Beyond this survey, numerous studies published in social science journals provide evidence of racial disparities in police decisions to make stops and in post-stop activities such as searches and arrests, in various jurisdictions around the country. For example, a recent study of “driving while black” examines racial disparities in traffic stops by state and local police in North Carolina in 2000. This study finds evidence of racial disparity in stops by local police officers, but weaker evidence of racial disparity in stops by state highway patrol officers.
 Both classic and contemporary research suggests that race influences decisions to arrest, either directly or indirectly. A recent study by David Kirk examines the role of social context in explaining racial and ethnic disparities in arrest. Prior social science research has shown that blacks are more likely than whites to reside in areas with high levels of concentrated poverty. So Kirk considers neighborhood context and its influence on arrests. He finds that disproportionate arrests of blacks are due in part to the fact that blacks and whites tend to reside in different kinds of communities with regard to socioeconomic status – which influences policing of the communities. But even after Kirk took into account neighborhood and other contextual factors, substantial differences in arrest remained between black youth and youth of other racial and ethnic groups. These remaining differences were unexplained in the research and could be due to discrimination.
 Much of the scholarly research on racial disparity in court processes has focused on the issue of sentencing. But researchers have also considered how race and ethnicity might be related to pretrial factors such as bail decision-making and type of legal counsel.
 Bail Decision-Making Generally, defendants can be held in jail prior to trial if they are considered a flight risk or a danger to the community. Several recent studies have examined how race and ethnicity affect the likelihood of pretrial detention, and provide evidence that race and ethnicity influence decisions regarding bail and pretrial detention, both directly and indirectly. One study, conducted in Washington in 1997, found that racial minorities were less likely than whites to be released on their own recognizance, and were more likely than whites to be required to pay bail as a condition of release. As a result, racial minorities were held in jail before trial at higher rates than whites. Given that people of color are more likely than whites to be poor, they are less likely than their white counterparts to be able to “make bail,” and so are more likely to be detained pretrial in part as a function of social class. The racial differences in this study remained even after the researcher took into consideration legally relevant factors that affect pretrial release, such as the perceived dangerousness of the defendant, any history of the defendant’s failure to appear in court, and the defendant’s ties to the community.
 More recent research, using data from the 75 largest U.S. counties, also showed that African Americans and Hispanics were more likely than whites to be held in jail prior to trial. Again, these effects of race and ethnicity remained even after the researchers took into consideration legally relevant factors; so we cannot say that minorities are more likely to be detained because they commit more serious crimes, have longer prior records, are more likely to have a history of failure to appear in court, and so on. There are several reasons for this racial disparity. It is mostly because minority defendants are more likely than whites to be held on bail, due to their economic inability to post bail. But it is also because minority defendants are more likely than whites to be denied bail, Hispanic defendants are less likely than others to be released on their own recognizance, and the amount of bail is higher for Hispanic defendants than for whites or blacks.
 The issue of bail decision-making is important – beyond the individual freedom at stake – because some have suggested that discrimination in bail decision-making has “spillover” effects on other court decisions. Those who are detained prior to trial are more likely to be convicted and to receive harsher sentences than those who are released pending trial – even after offense seriousness and prior record are taken into consideration.
 Type of Legal Counsel Given minority over-representation among the poor, it is not surprising that black and Hispanic defendants are more likely than whites to be represented by public defenders. There has been substantial debate over the quality of legal representation provided by public defenders who often have large caseloads, lack resources needed to prepare cases, and are underpaid (compared to district attorneys and private attorneys). Scholars also disagree about whether or not minority defendants are disadvantaged in the court system because of their heavier reliance (compared to whites) on public defenders. Some research suggests that the use of public defenders leads to harsher treatment of minority defendants, but other studies do not support this conclusion.
 A report published in 2000 by the Bureau of Justice Statistics (BJS) showed that conviction rates were essentially the same for those represented by public defenders and those represented by private attorneys. The vast majority of federal and state defendants in the 75 largest counties in the United States were found guilty, regardless of the type of counsel. However, the same report also showed that those represented by public defenders were more likely than those with private attorneys to be incarcerated. The report’s authors attributed this finding to differences in the types of cases represented by different types of attorneys. Public defenders represented a higher percentage of defendants charged with violent, drug, and public-order crimes, while private attorneys represented a higher percentage of defendants charged with white-collar crimes. Another study explored this hypothesis about why those with public defenders were more likely than those with private attorneys to be incarcerated. In this study, there was little evidence that type of attorney affected the odds of incarceration, once the researchers took into consideration the seriousness of the offense, defendant’s prior criminal record, and demographic factors. This study and the BJS report suggest that racial and ethnic minorities generally are not disadvantaged by their lack of access to private counsel.
 Sentencing Several years ago, Cassia Spohn conducted an extensive review of 40 studies on race and sentencing; my discussion of the influence of race and ethnicity on sentencing is based heavily on that review. Spohn argues that asking whether or not there is evidence of direct racial discrimination in sentencing is a simplistic and incomplete approach to a complex issue. She argues that, instead, we must ask, “When does race matter?” Under what circumstances, and in conjunction with what other factors?
 Social scientists researching the question of racial influence on sentencing make a distinction between direct, indirect, and interaction effects of race. Direct effects of race on sentencing mean that, in making their decisions, judges (in determining sentences) and prosecutors (e.g., in deciding whether to plea bargain) discriminate and base their decisions, at least in part, on defendants’ race. Indirect effects of race on sentencing mean that race influences sentencing through its effects on other factors, such as pretrial release, which in turn affect sentence severity. Interaction effects mean that race “interacts” or operates in conjunction with other factors in influencing sentences. For example, if we hypothesize that race interacts with age and gender to influence sentencing, we are not saying, for example, that blacks in general receive harsher sentences than whites. Rather, our hypothesis would be that specifically young, black males receive harsher sentences than others.
 So what does the research evidence tell us about direct, indirect, and interaction effects of race? The 40 studies that Spohn reviewed provide some evidence of direct effects of race and ethnicity on sentencing, but Spohn is cautious about overstating these direct effects. Based on her review of research, she concludes, “Although these findings suggest that race and ethnicity do play a role – a direct role – in contemporary sentencing decisions, it would be misleading to conclude that there is a consistent and widespread pattern of direct discrimination against black and Hispanic offenders in sentencing decisions.”
 But the 40 studies that Spohn reviewed provide significant evidence of indirect and interaction effects of race and ethnicity on sentencing. For example, these studies show that being held in jail before trial, being convicted at trial rather than by plea, and having a serious prior criminal record all lead to harsher sentences for racial and ethnic minorities than for whites. These findings suggest that race and ethnicity influence sentence outcomes through their effects on earlier decisions (e.g., pretrial detention, plea bargaining) – an indirect effect. The studies that Spohn reviewed also show that race and ethnicity interact with other characteristics of individuals to influence sentencing. Racial minorities are sentenced more harshly than whites if they are young, male, and unemployed, have relatively low incomes, and have limited education. Clearly, defendants’ race, in conjunction with these other factors, influences judges’ perceptions of which offenders are most threatening, most likely to offend again, and most in need of formal control by the criminal justice system. The race or ethnicity of the offender also interacts with that of the victim; racial minorities who victimize whites are sentenced more harshly than defendants in other combinations of offender race and victim race. Regarding indirect and interaction effects of race, Spohn concludes, “There is compelling evidence that offender race and ethnicity affect sentence severity indirectly or in interaction with other legal and extralegal variables.” Though sentencing guidelines and mandatory minimum sentences have constrained judicial discretion in the imposition of sentences, they clearly have not eliminated entirely racial disparities in sentencing.
 Obviously, there are many other facets of the U.S. criminal justice system that I could have explored in this discussion of racial disparity. But I have tried to keep the discussion brief, while still providing a sense of the many ways in which race and ethnicity come into play in the criminal justice system and impact incarceration statistics. The social science literature provides ample evidence of racial disparities at many places in the criminal justice system – for example, police deciding which neighborhoods to patrol most heavily and who to arrest rather than warn, prosecutors determining what charges to file against defendants, and judges being influenced by extralegal factors in sentencing decisions. All of these factors play a part in explaining the disproportionate confinement of racial and ethnic minorities in America’s prisons. And every one of these factors demands our concerted efforts at change – particularly given the ever-increasing size of America’s prison and jail populations.
 Bureau of Justice Statistics, Prisoners in 2007 and Probation and Parole in the United States, 2007 (Washington, DC: U.S. Department of Justice, 2008).
 Pew Center on the States, One in 31: The Long Reach of American Corrections (Washington, DC: The Pew Charitable Trusts, March 2009).
 Bureau of Justice Statistics, Prison Inmates at Midyear 2008 – Statistical Tables (Washington, DC: U.S. Department of Justice, March 2009).
 Bureau of Justice Statistics, Contacts between Police and the Public, 2005 (Washington, DC: U.S. Department of Justice, April 2007).
 For example, Kirk, David S., “The Neighborhood Context of Racial and Ethnic Disparities in Arrest,” Demography 45 (2008) 55-77. Warren, Patricia, et al., “Driving While Black: Bias Processes and Racial Disparity in Police Stops,” Criminology 44 (2006) 709-738. Alpert, Geoffrey P., et al., “Investigating Racial Profiling by the Miami-Dade Police Department: A Multimethod Approach,” Criminology and Public Policy 6 (2007) 25-56. Engel, Robin Shepard, and Jennifer M. Calnon, “Examining the Influence of Drivers’ Characteristics during Traffic Stops with Police: Results from a National Survey,” Justice Quarterly 21 (2004) 49-90.
 Warren, Patricial, et al., “Driving While Black: Bias Processes and Racial Disparity in Police Stops,” Criminology 44 (2006) 709-738.
 Kirk, David S., “The Neighborhood Context of Racial and Ethnic Disparities in Arrest,” Demography 45 (2008) 55-77.
 Bridges, George S., A Study on Racial and Ethnic Disparities in Superior Court Bail and Pre-Trial Detention Practices in Washington (Olympia, WA: Washington State Minority and Justice Commission, 1997).
 Demuth, Stephen, and Darrell Steffensmeier, “The Impact of Gender and Race-Ethnicity in the Pretrial Release Process,” Social Problems 51 (2004) 222-242. Demuth, Stephen, “Racial and Ethnic Differences in Pretrial Release Decisions and Outcomes: A Comparison of Hispanic, Black, and White Felony Arrestees,” Criminology 41 (2003) 873-907.
 Spohn, Cassia, and Miriam DeLone. 2000. “When Does Race Matter? An Examination of the Conditions Under Which Race Affects Sentence Severity,” Sociology of Crime, Law, and Deviance 2 (2000) 3-37.
 Spohn, Cassia C., “Thirty Years of Sentencing Reform: The Quest for a Racially Neutral Sentencing Process,” in Policies, Processes, and Decisions of the Criminal Justice System (Washington, DC: U.S. Department of Justice, 2000).
 Ibid., 474-475.
 Ibid., 476.