Fifty-two percent of students graduating from the Israel Arts and Science Academy in Jerusalem received an "outstanding" grade on their matriculation exams - the highest percentage among all high schools in the country.

According to data for the 2007-08 school year, published by the Education Ministry Sunday, the academy was rated far above the second-best school: the Albion Academy in Sajur, with 40.6 percent. Third was Horev, a private religious school for girls in Jerusalem (36.0 percent), fourth was the Baptist High School in Nazareth (31.2 percent), and fifth was the state religious school for girls in Ramat Gan (31.0 percent).

The lion's share of the 15 top-performing schools were semi-private, or "recognized but unofficial," institutions that receive some state funding, but also charge high tuition and accept only excellent students.

About 40 percent of the best performers were national religious schools, and 33 percent were Arab schools. Only 26 percent were ordinary secular schools.

About half of last year's 15 top schools also made the list two years ago; another five were ranked between 15 and 30 on the list of top schools in 2006-07.

To get an outstanding score, a student must have a weighted average of 90 or above if he took exams in a total of 30 or more study units, and 95 or above if he took 25 to 30 units. Only a few thousand students every year meet this standard.

The Israel Arts and Science Academy, run by an organization called the Society for Excellence Through Education, only accepts applicants who do well on its entry exam and it charges NIS 2,500 in tuition per month. But Hizki Arieli, director of the society, insisted that the real key to its success is "a high-quality, professional staff and the personal attention given to each student."

Ali Assadi, Albion's principal, said his school draws its students, most of whom are Muslim, from all over northern Israel. To be accepted, applicants must have had an average of 85 or higher in junior high.

The school is private, Assadi added, and none of the teachers have tenure: "If I see a burned-out or conservative teacher, I immediately get rid of him. The ability to choose the teachers affects the students' achievements."

Rabbi Oded Meislisch, Horev's principal, declined to say how much tuition the school charges, but acknowledged that there is an entry exam. He said the school places "a very strong emphasis on Torah combined with secular studies," and "the connection to values and excellence produces the results."

"I don't want to accuse the public education system, but the lack of schools from this framework on the outstanding list raises questions," he added.

But Prof. Chaim Adler of the Hebrew University of Jerusalem, an Israel Prize laureate in education, rejected the schools' explanations for their success.

"It's not hard to produce high scores if you have entry exams and demand high tuition from the parents," he said. "The public education system is left with the average or below-average students, because the best are drawn to the semi-private schools. But these 'private' schools are paid for by the state, which builds their buildings and contributes to their teachers' salaries. We mustn't delude ourselves: Without massive investment in the public school system, which still educates most students, our results will not improve."

Just last week, Education Minister Gideon Sa'ar termed the proliferation of "recognized but unofficial" schools "intolerable and warped."

"The ease with which private schools are established with public funds weakens the official education system," he said.