The "instructional sensitivity" of a test represents the degree to which students' performances on that test accurately reflect the quality of the instruction that was provided specifically to promote students' mastery of whatever is being assessed. In other words, an instructionally "sensitive" test would be capable of distinguishing between strong and weak instruction by allowing one to validly conclude that a set of students' "high" test scores are meaningfully, but not exclusively, attributable to effective instruction. Similarly, such a test would allow one to accurately infer that a set of students' "low" test scores are meaningfully, but not exclusively, attributable to ineffective instruction. In contrast, an instructionally "insensitive" test would not allow one to distinguish accurately between strong and weak instruction. This article describes the main features of a practical procedure for ascertaining the instructional sensitivity of any test, whether it is already in use or is under development. Because the instructional sensitivity of an accountability system's tests is the dominant determinant of whether that system helps or harms students, this approach should be used widely.