WASHINGTON, D.C. (CNN) -- American students can conduct successful science experiments at school, but aren't able to explain the results, new results from the National Assessment of Educational Progress show.

Results released today reveal that America's fourth-, eighth-, and 12th-graders struggled when investigations had more variables to manipulate or required strategic decision-making while collecting data. Many weren't able to explain why certain results were correct.

It's the first time the National Assessment of Educational Progress, known as the Nation's Report Card, measured how students performed on hands-on and interactive computer tasks like a professional scientist might. While traditional standardized tests grade students on what they know, people in the workforce are measured on how they apply what they've learned in school. This analysis moves away from "paper and pencil" tests and should allow for a different type of analysis by education experts.

The testing involved more than 2,000 students from public and private schools in fourth, eighth and 12th grades during the 2009 school year. In one task, 12th grade students were asked to determine the best location to build a town based on the quality of the water supply. The results show 75% of students could perform tests on water samples and tabulate data, but only 11% could "provide a valid final recommendation by supporting their conclusions with details from the data," according to the report.

"It's tragic that our students are only grasping the basics and not doing the higher-level analysis and providing written explanations needed to succeed in higher education and compete in a global economy," NAEP chairman David Driscoll said in a statement.

The report, "Science in Action: Hands-On and Interactive Computer Tasks from the 2009 Science Assessment," found that female students scored higher than their male counterparts on the hands-on on tasks, but male students scored high on the more traditional "paper and pencil" tests. No gender gap was found for interactive computer tasks.