New federally-compiled graduation rates for 47 states and the District of Columbia left many states reeling this week as more rigorous and uniform standards highlighted wide achievement gaps and lower numbers than previously reported.

While the U.S. Department of Education said the new rates can’t be compared to previous numbers, officials said the graduation rates provide an accurate ranking of states. Georgia, which has previously boasted graduation rates of about 80 percent, found itself near the bottom, with a graduation rate of 67 percent, even lower than neighboring states Alabama and Mississippi. “It’s disappointing,” Tim Callahan, spokesman for the Professional Association of Georgia Educators, told The Atlanta Journal-Constitution. “We were using sort of a feel-good calculation.”

And in Ohio, where state-calculated graduation rates have been climbing for several years, the state’s interim superintendent Michael Sawyers told the Newark Advocate that he’s “surprised and somewhat disheartened” to see that the graduation rate for black, Hispanic and low-income students is far lower than the 85 percent rate for white students. New Jersey, which had the highest graduation rate in the nation in a ranking by Education Week in June, tied with six other states for 12^th place. “I’m not sure there is any material difference between being in the top 12 versus the top eight,” said State Education Commissioner Chris Cerf to The Record. “It shows New Jersey is doing extremely well compared to the rest of the nation, and has significant room to improve.”

The move to a uniform system reflects a broader trend in education reform, as states also launch the new Common Core State Standards, which will allow more accurate comparisons of academic achievement. Under the new graduation metrics, all state scores are based only on the percent of students who graduate in four years, and data is adjusted for students who drop out or do not earn a regular diploma. Previously, states or outside agencies often included all students that graduated in any given year in calculating graduation rates, regardless of how long it had taken a student to finish.

The new data shows that even states with high graduation rates overall aren’t doing as well at graduating some student groups. Connecticut has an 83 percent graduation rate, one of the highest in the northeast. But when it comes to low-income students, only 62 percent graduate. (Connecticut also has one of the widest test score gaps in the nation between low-income students and their more affluent peers.) Minnesota has one of the largest gaps in achievement between black and white students, with a graduation rate for white students 15 percentage points higher than black. And in South Dakota, where 83 percent of all students graduate, less than half of Asian, Pacific Islanders, and American Indians earn their diplomas.

“By using this new measure, states will be more honest in holding schools accountable and ensuring that students succeed,” said U.S. Secretary of Education Arne Duncan. “These data will help states target support to ensure more students graduate on time.”

The lowest graduation rate was in Washington, D.C., where 59 percent of all students, and only 39 percent of students with disabilities, graduate high school on time. But D.C. does a better job of graduating black students than Minnesota and Oregon, and graduates a larger percentage of low-income students than Nevada and Alaska, all states with higher overall graduation rates.

Several states have relatively stable numbers across racial and income lines. Iowa, which claimed the highest graduation rate of 88 percent, had little variation in rates for different student groups, as did Texas and Arkansas.

This post was produced by The Hechinger Report, a non-profit journalism organization housed at Columbia University in New York.