Classroom size refers to the number of students (learners) physically present in a classroom. It generally excludes the instructor (explainer) and other observers who may be present. The reason for focusing on learners is that the learners are the ones whose learning experience is the typical goal of the classroom, and increasing the number of learners generally makes this more challenging (though it also offers some advantages).
- Student–teacher ratio measures the ratio of the total number of students to the total number of teachers at an educational institution.
- Maimonides' rule states that a classroom size must not exceed 40; any classroom with more than 40 students should be split into two. This is not to be interpreted as saying that a size of 40 is optimal in and of itself, but rather, that it is the maximum above which it is justified to have an overhead of an additional classroom.
Mechanisms of effect of classroom size and other confounding variables
The operation of cold calling
Further information: Cold calling
Cold calling is a practice where the explainer randomly selects a learner and asks the learner a question. Cold calling can assist with continuous assessment by both the explainer and the learners, and help avoid the illusion of transparency.
The dynamics of cold calling change dramatically with a change in the classroom size, which is the number of learners between whom the explainer can select. When the classroom size (i.e., the number of learners) is very low, then the cold calling has less of an element of surprise, and each learner gets called fairly often. This allows for more continuous assessment of each learner, but can also be more fatiguing to individual learners. As the classroom size increases, each individual learner is called upon less to support the same overall cold calling frequency. Up to a certain point, this increase might be worthwhile because it reduces fatigue for individual learners, and also gives both the explainer and learners more diverse, varied feedback on how learners are processing information.
However, beyond a point, an individual learner's likelihood of being cold called drops low enough that cold calling is no longer a way of systematically keeping the individual learner engaged.
The operation of polling
Further information: Polling
Polling for yes/no or multiple-choice questions generally benefits from larger classroom sizes, because we can collect more interesting data on the performance of each option, and drill down more deeply. Beyond a certain classroom size, efficient use of polling may require the use of technology like clickers (since a show of hands becomes too difficult to aggregate). In fact, lecture halls of hundreds of students can support and benefit from polling.