Because a class is smaller and discussion is more likely, some professors feel that simply introducing a topic related to reading is adequate to motivate students and promote learning. Small classes need structure just as lecture classes do. Further, many students lack instructional awareness and are unfamiliar with classes that require active learning. Without structure or sufficient experience on the part of students, small classes, simply because of their size, will not be effective ways for students to learn. Much of the advice for good teaching in large classes holds true for small classes as well.
Setting up small classes to work well requires significant time initially, and a great deal of attention particularly early in the semester with lower-level classes. As students gain experience and trust in the course structure, and as they gain confidence in their own skills, less work is required of the professor.
Adapted from Philip C. Wankat, The Effective, Efficient Professor: Teaching, Scholarship and Service, Boston: Allyn and Bacon (2002):