East Bay schools varied widely in student performance, according to rankings released Thursday by the state Department of Education.

The rankings, based on standardized test scores from 2009, range from 1 to 10, with 10 being the best.

In Alameda County, six of the 17 unified school districts — including Castro Valley — had 100 percent of their regular schools ranked in the top half of the state. Fremont was next, with 90 percent.

"We have done very well, but we would like our schools to be all 10s," said Maggie MacIsaac, assistant superintendent of curriculum in Castro Valley, where all of its schools received rankings of 8 or higher.

Hayward, with only 6 percent of its schools in the top half of the state, was ranked second from the bottom in the county as a district. Nine schools in Hayward also ranked in the bottom 10 percent statewide.

Three schools in Hayward face restructuring because of poor performance. The district is in the process of making severe cuts in the face of a state takeover. Superintendent Janis Duran presented an action plan earlier this year, making raising scores the top priority.

"How a school is faring in comparison to all schools in the state or to those similar in nature is of vital importance to parents, teachers, education advocates and the business community, who are all interested in student performance," Jack O'Connell, state Superintendent of Public Instruction, said in a statement.

The rankings are calculated from school Academic Performance Index, or API, scores, which range from a low of 200 to a high of 1,000.

The state has set a target API score of 800 for schools to show student proficiency in math and language arts. In general, schools ranked 6 or above met or came close to this goal.

Schools that failed to achieve API scores of 800 received growth targets to meet on standardized tests administered this month. If they fail to meet those targets when results are released in August, they could face sanctions under No Child Left Behind.

To view API scores and rankings, go to the California Department of Education website, www.cde.ca.gov.

Staff writers Eric Kurhi, Kristofer Noceda and Linh Tat contributed to this story.

API Rankings
Percentage of schools in each district that received a ranking of 6 or higher (on a scale of 1-10, with 10 being highest):
  • Castro Valley: 100
  • Fremont: 90
  • Hayward: 6
  • New Haven: 60
  • Newark: 20
  • San Leandro: 18
  • San Lorenzo: 44
    Source: California Department of Education