The Washington Comprehensive Assessment of Science (WCAS) measures the level of proficiency that Washington students have achieved based on the Washington State K-12 Science Learning Standards, which are the Next Generation Science Standards (NGSS).

The tests fulfill the federal requirement that students be tested in science once at each level: elementary, middle, and high school.

All students are assessed on their knowledge of the standards through the WCAS in grades 5, 8, and 11.