California Science Test (CAST)
The California Science Test measures the California Next Generation Science Standards (CA NGSS), adopted in 2013, in grades 5 and 8 and once in high school. The LEA chooses the high school grade - 10, 11, or 12 - and applies it consistently; grade 9 is not an option.
Three-dimensional design
CA NGSS performance expectations combine a Disciplinary Core Idea, a Science and Engineering Practice, and a Crosscutting Concept, and CAST items are written to that three-dimensional structure. Items are organized into clusters built around an anchoring phenomenon or design problem: a stimulus is followed by several items that ask students to interpret data, plan or critique an investigation, and explain mechanisms. Engineering design is embedded across the domains rather than reported separately. Item types are selected response and short constructed response scored with rubrics. The test is computer-based, untimed, and typically about 30–40 items.
Reporting
CAST reports one overall scale score and one of four achievement levels: Standard Exceeded, Standard Met, Standard Nearly Met, Standard Not Met. Unlike Smarter Balanced, it does not report claim or domain subscores. Students with the most significant cognitive disabilities take the CAA for Science instead.
Worked example
A grade 8 cluster gives a data table showing how much water four soil types absorbed, then asks for a claim about which soil best supports plant growth and the evidence for it. One student writes that sandy soil is best because sand is good for plants. Reasoning: this earns little or no credit. The response makes a claim without citing the table and without explaining the mechanism. A full-credit response names the soil with the greatest water retention from the data, cites the specific values, and links retention to what roots need, showing both the practice of argument from evidence and the core idea.
Traps that cost marks
- Preparing with isolated fact recall instead of phenomena-based, three-dimensional tasks.
- Writing a description of the data instead of a claim with evidence and reasoning.
- Expecting domain subscores on the student report.
- Assuming CAST includes a separate performance task component like ELA and mathematics; it uses item clusters instead.
- Scheduling the high school test in grade 9.