Graduation rates rose significantly for Charlotte-Mecklenburg Schools' black, Hispanic and low-income students in 2011, an important gain in a district where those groups make up a growing majority of students.

But the CMS rates still lag well behind those for the same groups statewide, as well as their white and Asian classmates in CMS.

Overall, 66 percent of CMS black students graduated in four years, up almost five percentage points over last year.

Sixty-four percent of low-income students graduated in four years, up four percentage points. And the 57 percent rate for Hispanic students is up almost 3 points.

Providence, a majority white south suburban neighborhood school, and Mallard Creek, a majority black neighborhood school in the UNC Charlotte area, both logged four-year graduation rates of 93 percent, topping the list of full-size CMS schools.

Cato Middle College High, a small specialty school that takes only academically strong juniors and seniors, hit 100 percent.

The latest graduation rates, along with test results released last week, show that the odds of academic success in CMS break out more strongly by high- and low-performing schools than by race or family income.

Some highly successful majority-black schools, including Cato, Berry (92 percent graduation rate) and Harding (89 percent), only take students who can read and do math on grade level when they reach high school. Magnet schools also tend to pull motivated students with families focused on education. Roughly two-thirds of students at the westside Harding and Berry came from low-income homes, but graduation and proficiency rates rivaled those at the most affluent suburban schools.

At Mallard Creek, a neighborhood school, three-quarters of students were nonwhite last year (mostly African-American), and about 40 percent were poor. Weak students are not screened out - but Mallard Creek students passed exams and graduated at high rates.

"It is a school that is focused on 'What do we do to help our kids get to the next level?' " said area superintendent Kelly Gwaltney, who was Mallard Creek principal until last month.

Gwaltney said major tests and papers account for 70 percent of students' classroom grades, which "places the emphasis on student performance." Students who do poorly can retake tests, but only after they've done more work.

Guidance counselors follow their students for four years to make sure they stay on track to graduate, Gwaltney said.

And parents - a mix of low-income families and African-American professionals - support the school, including its strict focus on behavior, attendance and being on time to class. After-school tutoring sessions are packed, she said, because parents insist on it.

"The school and the home, they're working together on what students need to graduate," Gwaltney said.

Waddell, a high-poverty neighborhood school that closed in June, logged CMS' lowest graduation rate at 51 percent, followed by West Charlotte at 54 percent. Those schools have long struggled with academic woes, and have seen gains in test performance in recent years.

The biggest eye-popper in the recently posted graduation report, a 64 percent graduation rate for Butler, is an error caused by faulty reporting from that school, CMS officials said Monday. Butler, a southeast suburban neighborhood school, traditionally logs strong results, and last year had an 85 percent graduation rate.

Chris Cobitz, the CMS administrator in charge of data and testing, said 131 Butler graduates weren't reported to the state. The error happened when school staff missed one of the computer clicks that would have made the grads part of the state tally, said Amy Brisley, assistant to Principal Will Leach.

Cobitz said the error was discovered after the June 30 deadline for correcting data for the August report. CMS has submitted a correction.

"We anticipate that once the state accepts the correction, the rate will rise significantly," Cobitz said.