The term "racial profiling" describes race-based selection of citizens for interdiction by police and other legal actors. Several studies have examined whether police disproportionately stop minority citizens who are either in cars or on foot; and, once stopped, whether police are more likely to search or arrest them compared with majority citizens. Whether or not these police interventions are racially motivated has been addressed in research, litigation, political mobilization, and internal scrutiny by police departments. The courts have generally held that a racially motivated stop may not be discriminatory under Fourth Amendment law if additional factors, such as the suspect's demeanor or contextual factors, constitute "reasonable suspicion" that the suspect may be involved in a crime; however, the courts have not offered a consistent standard for defining reasonable suspicion. The courts agree that police cannot stop, search, or arrest citizens solely based on their race. In practice, the inclusion of factors other than race as the basis for a stop opens the door for stops made on the basis of a substitution of the correlates of race for race itself. Whether police practices rise to a threshold of racial profiling or selective enforcement requires testing of the extent of racial disparities in police actions, under what circumstances, and the role of race relative to the rate of the targeted behaviors in the area under the patrol jurisdiction of the agency being examined. Different definitions and legal standards of profiling require different standards and tests. The central issue in any of these considerations, however, is whether the stops and searches were made because of race, net of other variables. This assessment of the uniformity of police actions "but for race" requires precise estimates of the supply of individuals who are engaged in similar behaviors. This article examines ways in which such an assessment can be made. As reliable information builds to facilitate the identification of racial profiling, this will increase the ability of citizen-police collaborations to regulate and manage racial disparities in policing. 66 references and 25 cited court cases