Students at Philadelphia's Strawberry Mansion High School failed to reach the state benchmark in the reading test last year, but by another state measure they showed a steeper rate of overall academic growth than those at the prestigious Masterman School.

The same is true of fourth to eighth graders in Delaware County's Upper Darby schools, many of whom failed to meet state standards. They showed more academic growth, on average, than children in the same grades in Garnet Valley, a high-achieving district in the western part of the county.

These comparisons illustrate the two ways the state measures performance. One shows if students have mastered the material they are supposed to know in a certain grade. The other shows how much they are learning from year to year, regardless of what level they start on.

Pennsylvania has long released results of the state PSSA tests, reflecting student achievement. Earlier this year, it began to show results for academic growth on a state website. This move was greeted with cheers from many frustrated school administrators who believe that their work helping students make gains, even if they are below grade level, has been underrated.

Student progress is tracked through the Pennsylvania Value-Added Assessment System . PVAAS has become an important tool for determining whether students are making satisfactory steps.

Using state test scores, it compares how much they actually learned with a statistical measure of how much they should have learned. It is the extent to which students made academic progress during one or more school years.

Ronald J. Tomalis, Gov. Corbett's nominee for education secretary, put the PVAAS data on the Education Department's home page with other links, under the heading "How is my School/District performing?"

"This is another way of helping parents become better armed with information and become more engaged . . . to support their schools and to raise concerns" when they are not doing well, Tomalis said.

State tests that students take every year, he added, show "snapshots of the academic performance of kids or schools." PVAAS, he said, gives an added dimension: "the movement - the progress - of kids over time."

School officials have long said that student academic gains are not always reflected in tests that measure only if students are achieving at grade level.

In Upper Darby, for example, where PVAAS shows students in most schools making gains well above the state standard and state averages, "many kids are coming to us two or three years below grade level, transferring in from schools outside the district," said Assistant Superintendent James Wigo.

PVAAS shows that the schools are "moving them toward proficiency year by year," Wigo said. "We are doing extraordinarily well by that measure."

In Philadelphia, academic progress in fourth to eighth grades is above the state benchmark and the state average. High schools don't do as well on average, though many individual schools show high progress rates.

"We're extremely happy and pleased that a large number of the schools do well on PVAAS," said David Weiner, the district's associate superintendent of academics. The system "makes you pay attention to make sure you focus on all the kids, not just those who are close to performing at grade level," he added.

Garnet Valley Superintendent Michael L. Christian said that some of the explanation for students' smaller academic gains there is that "traditionally high-performing school districts . . . may not show much growth because of our already high achievement."

PVAAS data, he said, are "valuable information but it doesn't tell us everything about our children." Arts and music programs or preparing students for future success by emphasizing problem-solving, not rote knowledge, he said, adds value not measured by tests. "You need to dive into what it means by looking at everything else our students are achieving" beyond test scores, he said.

Tomalis also said that PVAAS scores alone don't tell the whole story of a district. "Growth should not be the only measure," he said. "Sometimes it is easier to go from an F to a C than from an A- to an A. We should applaud schools when they make gains but we also have to understand how well they are doing overall."

PVAAS was developed to give educators a better picture of how students are learning over time and how well schools are teaching them. Tomalis said it would be put to many more uses in the future, including setting up "a 21st-century personnel system" that includes better measures of teachers' classroom skills and tenure and pay systems that reward high-achieving educators.

"We've learned that the effectiveness of a teacher is a critical factor in education, and PVAAS will help us measure that," he said.