Generally, those that use immediate recall of factual information as the measure of success find large classes slightly more effective or at least equally effective. Generally, faculty and students favor small classes, but some students prefer the anonymity of large classes. These variables interact with the class size question, making it hard to draw meaningful conclusions or recommendations across the board. Poise, good voice quality, and experience are also especially helpful for large class settings. In smaller settings, faculty who are more facilitative and flexible do well.
Many faculty can adjust their behavior to either setting, but most have a preferred mode.
Metaanalysis of research on class size and achievement.