Achievement gaps in the United States are observed, persistent disparities in measures of educational performance among subgroups of U.S. students, especially groups defined by socioeconomic status (SES), race/ethnicity and gender. The achievement gap can be observed through a variety of measures, including standardized test scores, grade point average, dropout rates, college enrollment, and college completion rates. The gap in achievement between lower income students and higher income students exists in all nations and it has been studied extensively in the U.S. and other countries, including the U.K. Various other gaps between groups exist around the globe as well. Research into the causes of the disparity in academic achievement between students from different socioeconomic and racial backgrounds has been ongoing since the 1966 publication of the Coleman Report (officially titled "Equality of Educational Opportunity"), commissioned by the U.S. Department of Education. The report found that a combination of home, community, and in-school factors affect academic performance and contribute to the achievement gap. According to American educational psychologist David Berliner, home and community environments have a stronger impact on school achievement than in-school factors, in part because students spend more time outside of school than in school. In addition, the out-of-school factors influencing academic performance differ significantly between children living in poverty and children from middle-income households. The achievement gap, as reported in trend data collected by the National Assessment of Educational Progress (NAEP), has become a focal point of education reform efforts by a number of nonprofit organizations and advocacy groups. Attempts to minimize the achievement gap by improving equality of access to educational opportunities have been numerous but fragmented. These efforts include establishing affirmative action, emphasizing multicultural education, and increasing interventions to improve school testing, teacher quality and accountability. Racial achievement gap The education of African Americans and some other minorities lags behind those of other U.S. ethnic groups, such as White Americans and Asian Americans, as reflected by test scores, grades, urban high school graduation rates, rates of disciplinary action, and rates of conferral of undergraduate degrees. Indeed, high school graduation rates and college enrollment rates are comparable to those of white Americans 25 or 30 years ago. It should also be noted that the category of African immigrant population (excluding Haitians and other foreign-born black people born outside of Africa) has the highest educational attainment of any group in the United States, but they represent a small group