Andrea, Too often it is assumed that students have the requisite skills and knowledge to begin their studies in a class. Whether they do, or should is one question, but the practical point is understanding where students actually are with their incoming knowledge. Of course, the pretest is one terrific method to get a handle on the overall level of the group. And as you point out, too much time may transpire before "weaker" areas are identified, and unnecessary backtracking may be required. Barry Westling