Blogs, Class Size, Power Rule

Perfect Class Size!

In Perfect Class Size-Prelude, I told you that the perfect class size is 12 students; however, I gave no explanation or justification thereof.  Here we will provide that explanation.

I have taught at 4 different colleges and a wide range of different math classes.  While teaching these courses, I have had anywhere from 1 to 120 students in a class at a time.  Yes, I have 1 student in a class (not an independent study).  With such drastic differences in class size, there is a large difference between my teaching approach for these classes.  Each of different class size brings its own challenges, but what class size offers the greatest opportunity for the students to learn?

Large Classes

Instead of focusing on the perfect size, I will instead look at what sizes would not be optimal.  The first such situation arises when you have a large class size.  In general, the larger the class, the less individualized attention you can give your students.  Even when teaching my class with 120 students, I wanted to stop and answer everyone’s questions during class.  I did actually do this for the first few classes; however, when I found myself two days behind after two days of class, I thought that this might not be a good approach.  Instead, I had to limit my responses to questions and continue with a lecture despite the fact that some student had gotten lost and were no longer following.

In order to address this issue, both I and my teaching assistants had regular office hours.  While some people did come, there were many others that were not able to or were not motivated enough to do so.  What ended up happening is that the students who understood the material from the lecture would have done so in any setting.  The motivated students that needed help were able to get it, but were required to do more work.  Then the students that had difficulties and were unable/ unwilling to seek help were left even further behind in the process.

This seems to be a fairly common occurrence in a large class size, and in fact there has been a wealth of research done on the topic.  There are many articles that address the difference in student involvement, achievement, retention, satisfaction and many other areas between large and small class sizes.  While I won’t refer to anyone in particular, there is a general concession that a large class is not optimal for the students, and is particularly detrimental to students that need more help.  While there may be discussion over what constitutes a large class, the effects of larger size seem to be apparent with as few as 20 to 25 students.

We therefore have that large class sizes result in

  • limited interaction in class, which leads to students getting lost,
  • increased difficulty in interacting outside of class, making it more difficult for student to catch up,
  • an increased likely hood that students that need help won’t be able to get it.
auditorium chairs classroom college
Photo by Pixabay on

Small Classes

If large class sizes are detrimental, would it not just be wise to have classes with one student?

The one-on-one instruction technique is a wonderful way to teach people.  While helping a student understand previously shown material is great in this manner, when covering a full classes worth of material, there are things that the student misses out on.  Having peers to interact with can be extremely beneficial to a student as they learn new material.

In the cases where I have had fewer than 5 students in a class, one of the major problems was that the pace of the class was directly affected by one or two individuals.

When there was a student that was having difficulty in the class, they had the ability to ask numerous questions, which I am inclined to answer with so few students in the class.  Yes this does help that student, but if the other students understand the material, they are left daydreaming while I respond to a question they already know the answer to.

On the other hand, if the students that do understand the material take over the discussion, you can spend time talking about generalizations and other results that are of a higher level than is really intended for students in the current class.  This then leads to the weaker students daydreaming while we talk about things that won’t be on an exam.

In a larger class this can still happen, but it is more difficult for an individual to take over a discussion.  The majority of students will be somewhere between these, and this is the group that has the most influence.  This helps in a classroom setting, because the pace itself can give feedback.  That is, if the student is having difficulty keep up, they know that they aren’t doing well and need extra help outside of class.  Furthermore, students who do understand the material aren’t given this impression falsely due to time spent on more advanced material.

In addition to the class itself, it is also helpful for students to work together.  This is why, despite the general hatred thereof, teachers give group work.  Students that understand the material can better their understanding by teaching others.  Those that need help, get to see the material from the perspective of a peer instead of the teacher, and this can often help them make a connection they otherwise wouldn’t.  Furthermore, there is then the opportunity for students to study together to ensure they look over everything covered, instead of just what they see first.

As a last note, students do tend to miss class from time to time.  If you were teaching them individually, you could just pick up were you left off; however, to have an entire class not show up is rather disheartening as a teacher.  I have indeed had a class of four where there were no students that came to class on a given day.  While it may be more of concern for me than the students, I would really like to not have this happen.

With regard to large classroom sizes, there has been enough research that we can pick out an approximate number that is too large to be optimal.   On the other hand, I was unable to find any research on a suggested minimum size of a class.  As such, I can only provide the anecdotal evidence of my experience and those experiences shared by others.  As such, I will go with a lower limit of 8 students in a class.

As a result, if there are too few students in a class,

  • students may receive skewed feedback on how well they are doing while in class,
  • students miss out on the opportunity to interact with, learn from, and teach peers.
girl in red short sleeve dress and flower headband holding pen and writing on paper on table
Photo by Pixabay on

The perfect size

What we’ve seen is that too many students in a class will lead to students getting less individualized attention.  However, having too few students in a class will deprive the students of the opportunity to interact with people at a similar level of understanding.  If we want the perfect class size, we should then avoid both of these situations.  As such, we should have a class size between 8 and 20 students.  In order to avoid the situation where you fall below the threshold because of absences, 10 or 11 students in a class seemed sufficient.

At this point, I really just thought, I don’t want an odd number, we couldn’t do pairs then.  But I’d also like to do group work.  While there is no reason you can’t have some groups of 3 and some of 4, I wanted something that could be equally divided into groups of either size.  Hence, we arrive at 12, the perfect class size.

group of people in conference room
Photo by Christina Morillo on

Let me know if you agree or disagree.  In particular, I’d be interested to know if you’ve had similar experiences to my small class size when homeschooling.  Does the lack of peer interaction seem to affect your children, or do you find ways to accommodate them with such interaction?  I would honestly like to know, as I have conflicting thoughts on whether or not to home-school my son when he is older.

If you liked the post, let me know by using the links below to like or share the post on Social Media.  I look forward to hearing your thoughts.


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