Language teachers have perhaps always known that diagnosing their students’ strengths and weaknesses early on in a foreign language course would, in principle, greatly facilitate their efforts to tailor instruction to the needs of particular students, or at least help them plan class activities appropriate for the general skill levels of the class as a whole. This, of course, is one of those many pedagogical insights that is much easier to talk about than act upon. Many of us forego diagnostics altogether and simply start teaching our class with Chapter 1 of whatever textbook we happen to be using, or perhaps by conducting some activity that has worked well for us in the past—all the while thinking that we’ll get to know the students pretty well in time.