Four New River Valley schools failed to meet state accreditation standards with their performance on last year's Virginia Standards of Learning exam, according to data released by the state Thursday.

Shawsville and Christiansburg middle schools in Montgomery County and Dublin and Pulaski middle schools in Pulaski County all had fewer than 70 percent of students pass math.

In all, 93 percent of the valley's 43 public schools are fully accredited, including all schools in Floyd County, Giles County and Radford. Statewide, 91 percent of schools are fully accredited.

To be accredited, a certain percentage of a school's students must pass the SOLs in English, math, history and science. The threshold varies by subject and grade. In most instances it is 70 percent, but it is 50 percent in science and history for grade three and 75 percent for English in grades three through five.

Schools that fail to meet accreditation undergo academic review by the state, and the oversight becomes more intense if a school fails to meet the standard four years in a row. That was the case for Pulaski Middle School, where the principal was changed and an 11-member oversight committee has been formed. The school is now classified as "conditionally accredited." Statewide, 28, or 2 percent, of schools have that status.

Christiansburg, Dublin and Shawsville middle schools are all considered "accredited with warning" for a second year in a row, which means that even if they fail to be accredited next year, they will have another year before facing more serious sanctions.

Tiffany Anderson, Montgomery County's superintendent, said she expects Christiansburg and Shawsville middle schools to be fully accredited "in the near future" because each school showed a double-digit improvement in the percentage of students passing math.

At Christiansburg Middle, 63 percent of students passed math, up from 53 percent in 2005-06. At Shawsville Middle, 60 percent of students passed math, up from 48 percent.

"If they have the same increase this year as they had in the previous year, then we certainly expect them to meet the benchmark," Anderson said.

"We are putting as many resources into those schools as we can possibly put," said Carol Jennings, assessment coordinator for Montgomery County Public Schools.

Two Montgomery County schools, Auburn Middle and Belview Elementary, were accredited this year after having failed to meet the standards the previous three years.

Anderson said Virginia Department of Education officials were filming at Auburn last week and planned to hold it up as an example of a "failing school" that had been turned around.