ABSTRACT
The tetrahedron offers us a kind of classification scheme if we want to use it in that way. Each of us has a favorite vertex, and most of us have a favorite edge for research. In general, all of us associated with educational institutions know that some students have superior test-taking skills and strategies whereas other have lower levels of these skills, less efficient strategies, and perhaps 'test anxieties' that prevent them from displaying what they remember. These may be extreme examples, but they may help us recognize that all criterial tasks involve skills and knowledge beyond that of the content that is supposedly being appraised. It is also known from motor skills research that what is measured by a criterial task, which objectively stays the same, changes with the stage of practice of the learner. Thus, Fleishman and Hempel showed that performance on the complex coordinator was differentially related to the measured abilities of their subjects.
