This article examines the validity of three recent efforts to improve
instructional assessment in mathematics for special education students
. In our view, to claim that an assessment is valid for informing inst
ruction, researchers must present evidence indicating that the assessm
ent information is in fact used by teachers as intended and that it re
sults in improved student learning. We use examples from the three res
earch efforts to illustrate these points and suggest fruitful areas fo
r further research. This discussion highlights crucial relationships a
mong constructs underlying effective practice and assessment in the co
ntext of the mathematics reform movement.