With the Obama administration focused on reducing the number of suspensions, expulsions and arrests in public schools, a new analysis of federal data identifies districts in 13 Southern states where black students are suspended or expelled at rates overwhelmingly higher than white children.

The analysis, which will be formally released Tuesday by the Graduate School of Education at the University of Pennsylvania, focused on states where more than half of all the suspensions and expulsions of black students nationwide occurred. While black students represented just under a quarter of public school students in these states, they made up nearly half of all suspensions and expulsions.

In some districts, the gaps were even more striking: in 132 Southern school districts, for example, black students were suspended at rates five times their representation in the student population, or higher.

In recent years, civil rights groups such as the Advancement Project and legal advocacy organizations including the NAACP Legal Defense and Educational Fund Inc. and Texas Appleseed have focused on reducing arrests and other severe disciplinary actions in schools.

Last year, the Obama administration issued guidelines advising schools to create more positive climates, set clear expectations and consequences for students, and ensure equity in discipline.

Still, “I am actually shocked that there is not more outrage,” said Shaun R. Harper, associate professor of education at the University of Pennsylvania and the executive director of the Center for the Study of Race and Equity in Education who was a co-author of the analysis.

Among the other findings in the analysis were that in 181 school districts where blacks represented just under 60 percent of enrollment on average, all of the students expelled during 2011-12 were black. Within the 13 states, Louisiana and Mississippi expelled the highest proportion of blacks.

Blacks were suspended or expelled at rates higher than their representation in the student body in every one of the 13 states analyzed. The report shows data for more than 3,000 districts.

“We want policy makers, parents and everybody to understand that any degree of disproportionality is in need of redress and response,” Mr. Harper said. The analysis did not look at suspension or expulsion rates for other racial minorities.

Michael Thompson, director of the Council of State Governments Justice Center, a nonprofit policy group, said blacks are more likely to be suspended or expelled in situations where teachers or school leaders have discretion in determining how to respond to behavior, such as when a student is deemed disrespectful or defiant or violates a dress code.

By contrast, in a study of students in Texas, Mr. Thompson and his co-authors found that in situations where laws require schools to suspend or expel a student — such as when the student brings a gun or drugs to campus — whites are more likely to be suspended or expelled than blacks.

The disparities existed in high-achieving as well as low-achieving schools. In Gwinnett County, Ga., a suburban school district near Atlanta, the new analysis showed that while fewer than a third of the students enrolled in the district were black, they represented close to half of all students suspended and more than half of all those expelled in the school year covered by the data.

The district has twice received a prize given by the billionaire philanthropist Eli Broad for strides in student achievement to large urban districts with high concentrations of minority students from low-income families. The Gwinnett County superintendent’s office did not respond to requests for comment.

The 13 states covered by the report were: Alabama, Arkansas, Florida, Georgia, Kentucky, Louisiana, Mississippi, North Carolina, South Carolina, Tennessee, Texas, Virginia, and West Virginia.

In addition to missing out on in-school learning time, students who are expelled or suspended are more likely to have later contact with the juvenile justice system than similar students who are not removed from school, studies have shown.

Some school districts have already begun to shift their policies to focus more on using counseling and trying to prevent or redefine problem behavior in the first place.

Mr. Harper said that education schools should focus more on raising awareness about racial disparities and prepare teachers to cope with tense situations without harsh discipline.

“This is at least partly attributed to people having these racist assumptions about black kids,” Mr. Harper said. “We argue that too little happens in schools of education to raise consciousness about that.”