When we rely upon gains on some measure to support statements of prescription, we have
the obligation to ensure that those measures are valid. The National Research Council
(2001) report Knowing What Students Know described three necessary components of a
valid assessment system: “a model of student cognition and learning in the domain, a set of
beliefs about the kinds of observations that will provide evidence of students’
competencies, and an interpretation process for making sense of the evidence” (p. 44).
We note that 10 years later, most measures still lack the first leg of the stool: an explicit
model of cognition