A response regarding an assay
I responded to a colleague's email this morning and thought it worthy of a post: Hi Ted-- Our accountability tests are necessarily uni-dimensional. That is, in order to generate consistent results over time we pick a single "construct," find "average" within the target population on that construct, and then measure out from that point to determine how far above or below average a student is (of course we don't use those terms, replacing them with numbers that sound less judgmental). That construct has to be uni-dimensional or "average" as the basis of consistent scores or the scores won't be stable over time. Thus a standardized test could be viewed as a sort of assay since it attempts to detect the degree to which a "thing" varies within a population. However, a standardized test--contrary to much popular belief--is only designed to measure the distance from average for a tested subject, which means it can never and has never...