The news was good for California's beleaguered public education system: More schools than ever scored in the upper reaches of the Academic Performance Index released Tuesday, hinting that when tests get tougher and standards get higher, students rise to the challenge.

The proving ground was the annual school-by-school ranking known as the API, comparing the state's 8,000-plus public schools, from Calexico High in the state's southernmost Imperial County to Hornbrook Elementary up north in Siskiyou County.

Based on last year's test scores, the API provides a snapshot of every school and district in the state.

This year, more than 1 in 5 schools, or 21.5 percent, scored in the desirable range of 800 or higher on the 1,000-point API, reflecting a high rate of proficiency on exams taken last spring. A year ago, just 15.5 percent of schools scored as well.

Bay Area schools performed even better, with 34 percent weighing in at 800 or higher -- up from 27 percent last year. The highest-ranking school in the state was Faria Elementary in Cupertino, which earned a near-perfect score of 996 points. The Bay Area also was home to the state's lowest-ranked school, San Francisco's Newcomer High, a haven for immigrants who speak no English. Newcomer scored 335.

Statewide, academic performance was highest in elementary schools, where 26.3 percent scored at least 800, up from 20.1 percent last year. Among middle schools, 15.6 percent scored at least 800, up from 12.7 last year. Just 7 percent of high schools performed as well, up from 4 percent last year.

"We are doing very well academically," state Superintendent of Public Instruction Jack O'Connell said in announcing this year's results. "But high schools need to become more of a priority for our state. Far too many of our 1. 7 million high school students are not being adequately prepared for college or careers."

Each year, every California school and district gets an API score ranging from 200 to 1,000, derived from tests taken the previous spring. The tests are the California Standards Test (with science for the first time); the CAT 6; the Exit Exam for grade 10; and, for the first time, the California Alternate Performance Assessment for students with learning disabilities.

Even schools and districts with an API below 800 are considered successful if they meet performance targets in the year to come. That target is set each year at this time at approximately 5 percent of the difference between their actual API and 800.

For example, San Francisco's Thurgood Marshall High scored 605 on the API this year. That means students will have to do well enough on their exams this spring to nudge Marshall's API up by 10 points, or approximately 5 percent of the difference between 605 and 800. Those results are reported in August.

Schools that fail to meet their targets two years in a row enter the state's school-improvement program. Persistent failure to improve leads schools and districts into "corrective action," and closures and takeovers are possible after five years. (Corrective action is part of the federal education act of 2001 known as No Child Left Behind. No schools have yet been closed under the law.)

In addition to the overall API score, each school is also ranked from a low of 1 to a high of 10 -- twice.

A "statewide" 1-to-10 ranking is derived from a school's API when compared with all APIs in the state. In the Bay Area, 19 percent of schools (271) earned a 10 this year.

A second 1-to-10 ranking of "similar schools" is derived from a school's API score when compared with the APIs of 100 schools with similar demographics. The idea is to see how a school stacks up when such conditions as poverty and parents' education are considered. In the Bay Area, 8 percent of schools earned a 10 on the similar-schools ranking.

But demographic data can be manipulated in certain cases, making that ranking somewhat less reliable, state officials acknowledged.

For example, Cherry Chase Elementary in Sunnyvale appears to be the state's highest-ranking school with large numbers of poor children (except for San Francisco's Lowell High, where student admission includes screening for high scores). Cherry Chase scored a whopping 919 on the API and ranked a 10 on the statewide list and against other schools with poor children.

But Cherry Chase has virtually no poor kids enrolled. "I can confirm that, " said Principal Erica Tukeman.

As a result of reporting irregularities, Cherry Chase's economically advantaged students were erroneously compared with disadvantaged students elsewhere, virtually ensuring a 10 for Cherry Chase while making it harder for others to rank as high.

The same kind of error occurred at Henderson Elementary in Benicia, the Bay Area's next highest-scoring school in which poor kids and low parent education were reported. But again, this school has no such students and instead has predominantly well-off kids from well-educated families.

Principal Roberta Horack said she was as surprised as anyone to learn that low-income students were reported at her school. "It's unfair to schools compared with my school," she said.

Bill Padia, the state Education Department's API expert, said schools had many months to correct the data and that the similar-schools ranking for the two schools will be invalidated.

"They had an obligation to make this right," he said.

The snafu underscores what many educators know to be true: Numbers do not tell the entire story.

"The numbers represent one slice of education," said David Eisenbud, director of the Mathematical Sciences Research Institute in Berkeley, where a conference on student math testing is under way. "Scores certainly don't represent an overall measure of the quality of education students are getting. For that, you have to see what's going on in the classroom."

Meanwhile, Principal Dolly Travers of Faria Elementary said, "We're rattled and stunned and delighted and proud" to be ranked at the top of all California schools -- even outscoring those with equally well-to-do students with highly educated parents. Travers credited a school environment where teachers meet regularly, have a common vision -- and enjoy each other and their students.

To the north in San Francisco, Principal Herb Chan of Newcomer High expressed equal pride in the state's lowest-ranked school.

"Students want to come here," he said. "This is a safe environment where there's no stigma for not knowing the language." The worst thing about Newcomer is not its low API, Chan said, but that students are only permitted to stay for one year before being placed in a traditional school.

The Bay Area is also home to the state's top-ranked district, Los Altos Elementary District in Santa Clara. There, teacher turnover is low and respect for instructors is high, said Margaret Gratiot, the district's superintendent for 17 years.

Emery Unified in Emeryville is the Bay Area's lowest-ranked district. Now back on its fiscal feet after the superintendent quit in disgrace in 2000 and was convicted of misusing public funds, the district still has to find its academic footing. Emery's staff turnover has been high, and it has had no consistent vision -- until now.

Joe Frantz, the curriculum director hired last year, said the district has at last begun to identify and help students who read and do math below grade level. It is reorganizing students into smaller groups, providing extra training and planning time for teachers, and hiring specialists in core academic subjects. Frantz said the district can pay for the additional services as a result of a new $1.4 million per year parcel tax.

"We're expecting to see dramatic improvement beginning this year," Frantz said. "I expect we'll see a lot of changes."

For the full report, visit www.cde.ca.gov/psaa/api.

    Academic Performance Index
    Here are the Bay Area schools that ranked in the top and bottom of the 
API test given last year.

   Top 10

   School                         City             Score
   Faria Elementary               Cupertino         996
   Portal Elementary              Cupertino         989
   Millikin Elementary            Santa Clara       983
   Gomes Elementary               Fremont           979
   Mission San Jose Elementary    Fremont           975
   Weibel Elementary              Fremont           973
   Sleepy Hollow Elementary       Orinda            970
   Dilworth Elementary            Cupertino         970
   Hoover Elementary              Palo Alto         965
   North Star Academy             Redwood City      964

   Bottom 10

   School                         City             Score
   Lowell Middle                  Oakland           491
   Simmons Middle                 Oakland           475
   East Palo Alto High            East Palo Alto    472
   Mission High                   San Francisco     472
   Kennedy High                   Richmond          449
   McClymonds High                Oakland           446
   Fremont High                   Oakland           444
   Castlemont Senior High         Oakland           422
   Rudsdale Academy               Oakland           417
   Newcomer High                  San Francisco     335

    Source: Department of Education