Classroom discussions create an opportunity for teachers to lead a class through a subject and build upon students' knowledge. Unfortunately, this is sometimes at the expense of less active students and creates a time-consuming process that restricts a teacher's ability to plan lessons. The risk of going off track with the discussion is another problem, and these issues grow as the class size grows. While a classroom discussion is ideal in the right environment, it may not be so perfect for some classes.

Class Size

Class discussions become less effective with a class size greater than 20 students. As the class size grows beyond this point, individual voices become unheard and the opportunity for the class to get off topic increases. Skilled teachers begin to notice this problem with fewer than 20 students, but with effective class management you can hold your class together.

Few Dominate

The class discussion environment allows a few individual students to dominate the class conversation. This tendency benefits your strongest students, the individuals already most familiar with the subject. Other students are able to relax into the background and participate less often in the class discussion. This freedom leads to a relaxation of their student responsibilities. They are free to assume that they can avoid studying, reading assignments or individual contemplation of the subject. This problem escalates as the class size increases.

Time Consuming

The nature of class discussion makes the process very time consuming. The process of exploring a subject, while keeping students on task in the discussion, requires far more time than classic lecture style instruction. Short class periods may not be sufficient to accommodate a complicated subject matter or to fully explore a daily objective. This forces you to either abridge your lesson plan, leave a subject unfinished or resume the discussion during another class period in which you had intended to discuss another matter. Additionally, it is difficult to judge the necessary length for specific issues, making designing lesson plans very challenging.

Off Track

Classroom discussions naturally open avenues for discussion between instructors and students but also between students and other students. While these discussions are the focus of the class, they can turn toward areas you do not intend and even move entirely away from the point of the discussion. While it is possible to redirect an errant conversation back on track, valuable class time is lost and you risk losing your student's focus on the subject matter.