Raleigh, N.C. — More North Carolina schools met or beat expected academic growth this year, state education officials said Thursday, but they cautioned against comparing the results with previous years because reading scores weren't part of this year's results.

Fifty-five percent of public schools statewide posted high academic growth in 2007-08 as measured by the state's ABCs of Public Education accountability model. Another 27 percent earned expected academic growth under the model.

Academic growth is calculated by comparing students' academic performance from year to year and comparing that growth to what was typical in prior years across the state.

Last year, about 72 percent of schools met or beat expectations.

The growth measurements for elementary and middle schools are usually based on reading and math test scores, but new reading assessments were used this year, so the latest results are based only on math scores, officials said.

For high schools, growth is calculated using end-of-course tests results, dropout rates and participation in college preparatory courses.

Teachers, principals and other school staff receive incentive awards based on their school's growth designation.

The 2008 state budget capped the total incentives at $94.3 million, so bonuses had to be cut by about 30 percent, officials said. Teachers and principals at high-performing schools will receive $1,053 this year, while those at schools meeting expected growth will receive $527.

Eighty-four percent of Wake County schools met or exceeded the ABCs standard, as did 67 percent of Durham County schools. All 17 schools in Chapel Hill-Carrboro met or exceeded the standard.