Final answer:
The grid that served as a guide when constructing an achievement test is called a blueprint.
Step-by-step explanation:
The grid that served as a guide when constructing an achievement test is called Blueprint. A blueprint is a detailed plan or design that outlines the content, structure, and organization of the test. It specifies the number and type of items, the distribution of items by content area and difficulty level, and the intended learning outcomes that the test aims to measure