Drake Pinkston, one of last year's Clayton High School sophomores, wasn't surprised the 15-year-olds in his class topped other students from countries worldwide on two categories of an international assessment test.

"Our students are very talented," said Drake, who is now 16 and the junior class president.

The test gauges students' readiness to tackle real-world challenges in a number of subject areas.

Results from nearly 200 Clayton students who took the test showed they finished first in science and reading and second in math in the Program for the International Student Assessment (PISA).

"I thought we were absolutely prepared and PISA wasn't too much of a challenge for me," Drake said. "Our teachers thoroughly explained what the test would be about so we weren't blind-sided by it."

PISA assessments focus on 15-year-olds' understanding of concepts in reading, math and science literacy and problem solving abilities. The test is given to students in more than 70 countries, including the U.S.

More than 200 Clayton High School 15-year-olds took the PISA during the 2009-2010 school year.

For the test, students formed what effectively was their own country to take part in PISA, said Superintendent Mary Herrmann.

The district chose to take part in PISA due to an invitation to participate in a larger research study of sophomores in 100 school districts nationwide, conducted by the ACT college entrance exam organization.

"But Clayton wanted to test the capabilities of all its sophomores, rather than the small percentage of them in the 100 districts taking part in the ACT research study," said Herrmann, adding the PISA test cost the district nothing.

No other local districts took part in that PISA test, she said.

While all sophomores last school year took the assessment, only 176 of their results were counted in the comparison data because PISA required that students had to be 15 to make the test comparable internationally.

Herrmann admits test results reflect how certain students did on specific questions at a single point in time.

"But the results are helpful and affirm that our students are performing well and we need to continue to work toward enhancing that global competitiveness," Herrmann said.

Results point to talented students, good staff and a highly supportive community, she said.

"We have high expectations for high levels of performance here," Herrmann said.

Begun in 2000, PISA is administered every three years.

Herrmann's not sure if there will be an opportunity for Clayton students to take the test again.

"For an individual district to be able to access PISA was unusual, and we only did it because we participated in that one-time ACT study," she said.

While Clayton did better than the overall U.S., "we're mindful that a lot more kids took PISA tests nationwide, though we didn't take part in that nationwide PISA test," Herrmann said.

"Our results are a credit to our asking the question of how we'd do globally, stretching ourselves and finding out, to get a good benchmark," Herrmann said.

Clayton Board of Education President Sonny Buttar said that even though the PISA results are only a snapshot in time, "they reflect generations of community support."

Dee Luo, 16, was also one of those who took the test at Clayton.

"The test wasn't what I expected — in sophomore year, we also were exposed to parts of the PSAT which seemed more difficult than this one," she said.

"I'm delighted we placed so high in some categories, but I'm not sure about the comparisons between us and the rest of the world, since we were compared to other countries though we weren't a country," she said.