Only one-fifth of high school seniors in 2009 were at or above proficiency level in science, according to the results of a nationwide test released Tuesday.

Of the approximately 11,100 seniors tested in the National Assessment of Economic Progress in early 2009, 21 percent reached proficiency level or above in science. This percentage was smaller than for any other subject tested since 2005 except for U.S. history. Stephaan Harris, spokesman for the National Assessment Governing Board, said the lack of proficiency among students could reduce their opportunities.

“Many members of the board have a general concern about the lack of science proficiency because it’s connected to so many careers,” he said.

Harris said multiple factors may have caused the lack of scientific knowledge and he could not predict if science proficiency would increase or decrease in coming years. Because the Department of Education changed the test since it was last administered in 2005, the latest results don’t show how science proficiency has changed in recent years.

Harris said science proficiency would improve if students engaged in more science activities in and out of school and took more science classes.

“Students who took several years of science in high school tended to score better than students who took fewer science classes,” he said.

Jerry Brand, a UT molecular cell and developmental biology professor, said high school teachers should remind students of what they should know when teaching concepts that depend upon previous knowledge.

“It’s impossible for anyone to go abruptly from one step to the other without disruption,” he said.

Brand said the separation of scientific discipline requires students taking standardized tests to remember information they learned years ago. He said integrating disciplines when discussing topics such as photosynthesis could improve the range of student knowledge, but this is not feasible under the current system.

In the report, 32 percent of American fourth grade students were proficient in science. Brand said it is difficult for students who weren’t proficient in earlier grades to become proficient later.

“Facts and principles build,” Brand said. “Students who get behind stay behind.”

Biology senior Landon Cunningham said the regular biology and chemistry classes he took in high school did not prepare him for college-level science.

“It was just a lot different the way the material was taught and how much more was expected from you — to read in-depth to the topic versus having an outline given to you,” Cunningham said.