Three-quarters of Indiana's public high schools failed to meet state standards for academic improvement during the 2009-2010 school year, a figure the state's top education official said Tuesday shows schools are failing students once they reach high school.

The state Department of Education said 75 percent of Indiana's 385 public high schools are ranked in the bottom two rungs of the state's five-tier ranking system. Nearly half are on the lowest level — academic probation — and 20 schools in their fifth year of probation could face intervention or even state takeover.

"I think it is a huge number. And I think it is very concerning," state schools Superintendent Tony Bennett said.

The percentage of high schools on probation was up from 10 percent in 2008, the last year for which data were available due to a switch to spring standardized testing. Overall, the number of all schools on probation was 14 percent, the department said.

About 19 percent of Indiana's public schools fell into a lower category this year than in 2008. And about 42 percent moved into higher categories, while the rest stayed in the same tier.

While elementary and middle schools have shown improvement under the state's 11-year-old accountability system, high schools continue to decline, Bennett said. "We really begin to see serious declines in student performance at the high schools," he said.

Bennett said schools must figure out what they need to do to meet the needs of students once they reach high school and prepare them for college or work.

"We have to raise our level of expectations, we have to raise the rigor of instruction and we have to increase the relevance of instruction," Bennett said. "We are losing far too many students in these schools."

Jonathan Plucker, director of Indiana University's Center for Evaluation and Education Policy, said some of the dip in high school performance may have been due to changes in standardized testing procedures, including the switch to spring testing and basing high school results on algebra and English instead of a graduation exam. But, the decline from elementary to middle to high school was a national phenomenon. Federal data released last week showed a similar trend, he said.

"Improvement in high school is just proving to be so much harder," Plucker said. "Student performance tends to suffer as we go through the system."

No one knows whether the real cause is socioeconomic, cultural, lack of parental support or something else, he said.

Plucker said the country may need to rethink its whole approach to high school education.

"It's not getting better. It appears to be getting worse. We need to do something here," he said.

Bennett said he was prepared to make "strong recommendations" about intervening at high schools on probation if they don't improve by the end of the school year.

"The clock is ticking," Bennett said.

Meanwhile, the number of schools meeting federal progress standards under the No Child Left Behind law increased to 58 percent from 50 percent in 2008, with particularly strong gains among poor and minority students, according to results released by the state agency Tuesday. Bennett attributed part of those gains to the increased use of statistical and scoring data to drive instruction at elementary and middle schools.

The state rankings are separate from federal accountability measures required under the No Child Left Behind law, though both were released the same day. The federal progress goals only account for performance on statewide exams, while the state rankings give credit to schools for both performance and improvement over time. Consequences of the federal law only apply to schools receiving certain federal funding, while the state consequences apply to all public schools except charter schools.

State education officials are working on revamping Indiana's accountability system and hope to seek a federal waiver next year to replace the current dual improvement system with a single state system, Bennett said.