I have taught Introduction to Sociology at a large university and a small commuter campus, during the spring, summer, and fall, with classes ranging from 15 to 65 students. In each of these settings I followed the same basic format and in each of these settings I achieved what I considered to be success based on the performance of my students. As a result, my intro class was the least of my worries heading into my first semester at a liberal arts school. Then 1/3 of my intro students failed the first exam.
Beyond the fact that I try to maintain an even temperament, the fact that I had successfully taught intro in all of those different places is probably what prevented me from freaking out (I guess that point number 3 here is important to note). As a result, I ended up writing the performance of my students off as another symptom of their freshmenness. Of course, blaming the freshmen will not get you very far if you don’t work to help them. Before the second exam I spent quite a bit of time going over student answers to questions on the first exam, making my expectations even clearer, and talking about studying techniques.
In the end, students did much better on subsequent exams and their final grades were only slightly lower than in all of those other settings. Without my teaching experience I don’t know if I would have blamed myself or my students. As usual, the reality was somewhere in between.