if we want to measure the mathematics proficiency of eighth-graders, we need to specify what knowledge and skills we mean by “eighth-grade mathematics.” We might decide that this subsumes skills in arithmetic, measurement, plane geometry, basic algebra, and data analysis and statistics, but then we would have to decide which aspects of algebra and plane geometry matter and how much weight should be given to each component. Do students need to know the quadratic formula? Eventually, we end up with a detailed map of what the test should include, often called “test specifications” or a “test
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