Reducing class sizes is a commonly discussed goal in education. However, there may not be a more consequential educational issue where the academic research available is a poorer match to anecdotal evidence than the issue of class size.

Ask any teacher, administrator, or parent you know what they would prefer, and almost all of them will say that smaller class sizes are more conducive to learning than larger class sizes. Peruse any higher education website and you will find most try to trumpet their low student to faculty ratio. And, intuitively, it just makes sense that students will learn better if there are fewer of them in a class.

But, there is actually very little academic evidence that class size matters. Our review of the literature indicates that there is some evidence (gathered long ago) that smaller class sizes have an effect at the youngest grade levels, but little or inconclusive evidence that smaller class sizes matter among older students.

Yet a debate rages regarding class sizes. Teacher unions are understandably in favor of lowering class sizes, as this makes the job of the teacher easier and increases the numbers of teachers that need to be hired. Administrators seem to also favor lowering class sizes, but are wary to do so without much evidence indicating that it will improve academic achievement. Politicians favor it as well, as reducing class sizes certainly sounds like ad admirable goal to pursue.

What is undebatable is that there are significant costs involved in decreasing class sizes. Reducing class sizes means building more classrooms, maintaining larger facilities, and hiring more teachers.  The costs of reducing class sizes are potentially large, which is why it is surprising the issue doesn’t have much academic study and thought behind it.

We feel the issue has been oversimplified. Like most things we study, there are likely decreasing returns as class size is reduced. In other words, there is likely an ideal level for class size. There is probably a point where a class size can be too small, as tiny class sizes don’t allow for student-to-student learning and collaboration, small group projects, etc. As class size increases, it likely hits an ideal point, where the learning efficiency of the classroom is maximized. And, invariably, a class size can grow too large, where supervision of students is compromised.

It is possible that the academic studies that are available have not investigated a wide enough range of class sizes and therefore have not been able to spot this ideal point. Since no school district could (by law) change its average class size by more than a few students, academic researchers are likely concentrating on class size differences that are not large enough to show much of an effect.

However, in the debate over class sizes, there is an important issue we have never seen discussed. It is that the ideal class size is likely not the same for all situations. Even within a school, the ideal class size likely varies by the subject taught, the academic capabilities of the students, the grade level, and importantly, the particular strengths and weaknesses of the teacher.

For example, why do we presume that the same class size is needed for English as is needed for Math, or Foreign Languages? Why do we presume that 7^th graders need the same class sizes as 12^th graders? Or that a first-year teacher will be most efficient teaching the same class size as a proven teacher with 20 years of experience? Or that every student benefits most from the same class sizes?

We ignore the variability that is inherent in the process.  And, we don’t give our school managers (School Principals) much leeway in how they can manage their resources to take into account this variability.

We’d like to see Principals given a lot more latitude over how to best utilize their staff. In any organization whose success is dependent on the capabilities and productivity of its workers, the main task of a manager is to understand his/her staff’s capabilities and knowing how to properly deploy human resources.

Currently, Principals are given almost no latitude regarding class sizes. The Principal is forced to take a cookie cutter approach – with all teachers being assigned virtually the same number of students. A teacher is largely given the same responsibility on his/her first day on the job as his/her last day. Regardless of his/her subject, experience level, talents, teaching style, grade level, etc.  The teaching staff is the most important asset a Principal has to achieve academic excellence, and it is time to give Principals more responsibility in this area.

Class size absolutely matters. Just not in the same way and same level for every school, teacher, and student.