The TELS approach to assessment focuses on measuring how successfully students evaluate and change their perceptions about science in light of new information. This approach offers insight into both the overall benefit of TELS projects and the specific impacts of scientific simulations. The TELS assessments ask students to link and connect ideas and give explanations for their conjectures, consistent with the knowledge integration framework that guides design of TELS curriculum materials. TELS researchers have created a knowledge integration scoring rubric to code responses to the items.

TELS created six TELS benchmark tests, each composed of some research-based and some standardized items measuring knowledge integration. The tests cover middle school physical science, life science, and earth science, as well as high school biology, chemistry, and physics.

We have analyzed pre-test and post-test performance for projects undertaken during the first year of our program. For every project studied, students have shown a significant improvement in integrated understanding. For example, students earning high and low pre-test scores all make significant progress in understanding complex science, such as explaining how chemical reactions produce greenhouse gases.

Embedded assessments provide precise information about student learning on a minute-by-minute basis. Many TELS projects embed assessments prior to and following the use of scientific visualizations to gain insight into the impact of these visualizations on student understanding. For example, in the Electricity project, Casperson and Linn (2005) found that students' understanding of electrostatics, and specifically the concept of induction, was facilitated by the prior use of a visualization that captures elements of both the macroscopic and atomic-scale nature of electrostatics.