Saturday, February 17, 2024

The Science of Classroom Size : Rethinking Classroom Size Based on Real-World Models

The Optimal Classroom: Re-evaluating Size and Structure for Effective Teaching and Learning

Abstract

Class sizes in American public schools have steadily grown over the past decades, with the average classroom now containing over 25 students. Research clearly shows the benefits of smaller classes on student achievement, especially in earlier grades. Yet systemic pressures prevent widespread implementation of reduced class sizes. This literature review analyzes evidence on ideal classroom sizes and teacher-student ratios for academic success, social-emotional growth, and classroom management. It further explores the military model of small working groups under hierarchical leadership as a potentially effective organizational structure for large schools and classes. Research on team dynamics, group roles, and span of control provides additional insights into optimizing classroom leadership. Synthesizing best practices in education, psychology, and business management leads to propose a new staffing model: classroom sizes of approximately 15 students, with a lead teacher facilitating most instruction and an assistant providing individualized support. This structure balances educational research, practical constraints, and organizational effectiveness to best enable excellent teaching and enriched learning.

Introduction

Class sizes in public schools across the United States have risen steadily for decades. Average class sizes now exceed 25 students in many states, with ratios approaching 30 or more in some districts (Sparks, 2021). Teachers and parents have decried these large classes and heavy student loads as detrimental to providing all children a quality education. Yet systemic budget limitations and educational policies focused on efficiency prevent widespread implementation of class size reduction reforms.

Meanwhile, the typical structure of a single teacher lecturing to a room full of students remains the norm. This format is inherited from an industrial-era model of schooling for mass education. But research in pedagogy and child development suggests that alternative structures may better serve students’ diverse academic and socio-emotional needs. Studies of team dynamics and leadership in fields like business management further illuminate effective group organization.

This literature review synthesizes evidence across disciplines to address two key questions:

1) What classroom size best enables student learning and healthy development?

2) How should classrooms be structured and staffed to create optimal conditions for teaching and learning?

Analyzing empirical studies and conceptual models leads to propose a new staffing approach: limiting class sizes to approximately 15 students, with a lead teacher facilitating most instruction and an assistant providing personalized support. This structure balances pedagogical research, practical constraints, and organizational effectiveness. Creating appropriately sized classes with a dual teaching model may significantly enrich the classroom environment to benefit both students and teachers.

The Case for Small Classes


Extensive research documents the academic and social-emotional benefits of small classes, especially in early elementary grades. Class size reduction emerged as a major education reform movement in the 1980s after Tennessee’s Project STAR demonstrated that placing students in classes of 13-17 students in grades K-3 significantly improved test scores, even when controlling for potential confounding factors (Finn et al., 2001). Follow-up studies found lasting impacts on achievement through middle school and increased likelihood of taking college entrance exams, suggesting small early classes have long-term effects (Konstantopoulos & Chung, 2009).

These benefits appear most pronounced for students from disadvantaged backgrounds. Krueger & Whitmore (2001) found that reducing class sizes in early grades from 22-25 students down to 13-17 students could help close the black-white achievement gap by approximately one third in math and one fifth in reading. Dee & West (2011) similarly found sizable improvements in achievement among poor, minority, and male students when placed in small classes.

Several interrelated factors contribute to the advantage of small classes. Teachers can provide more individualized instruction, feedback, and support to each student (Blatchford, Bassett, & Brown, 2011). Students have more opportunities to actively participate and learn collaboratively with peers (Zahorik, 1999). Teachers can better monitor student progress and tailor lessons to varying ability levels (Gilman & Antes, 1985). Classroom management is easier with fewer students, allowing more time spent on meaningful instruction (Biddle & Berliner, 2002). Smaller classes also create a warmer socio-emotional climate and more positive student-teacher relationships (Finn et al., 2003).

Conversely, large classes negatively impact learning motivation, on-task behavior, and discipline issues (Blatchford, Edmonds, & Martin, 2003). Teachers feel overwhelmed, strained, and burnt out trying to meet all students’ needs, which may lead to increased teacher turnover (Graue, Hatch, Rao, & Oen, 2007). Large classes also decrease the amount of individual teacher-student interactions and student engagement during lessons (Blatchford, Bassett, Goldstein, & Martin, 2003).

Research suggests the ideal class size for academic achievement falls in the range of 15-18 students, after which benefits begin to diminish (Glass & Smith, 1979; Achilles, 2012). Class sizes under 20 show the strongest positive impacts, especially in early grades and high-poverty schools (NAESP, 2013). Yet the average American elementary school class still contains 21-26 students depending on district and state (Sparks, 2021). Reducing average class sizes from 23 down to 15 students could improve student learning equivalent to about 3 additional months of schooling (Krueger, 2002). The long-term returns on investment are also substantial, with economic analyses estimating savings from higher earnings and reduced social costs of $168,000-$264,000 per student over their lifetime from small K-3 classes (Muennig & Woolf, 2007).

Despite this compelling evidence, systemic barriers like insufficient school funding, facilities, and staffing prevent widespread implementation of class size reductions, especially below 20 students per class. However, some countries have adopted policies that cap class sizes at much lower levels – such as Denmark’s 18-student limit in early grades (Pedersen, 2018) – demonstrating this reform is feasible given adequate resources and political will. Within budget constraints, school leaders can still optimize class sizes to maximize learning.

Alternative Classroom Structures

In addition to class size, the typical configuration of one teacher lecturing to an entire group of students may not be the only or optimal structure for organzing a classroom. Alternative models introduce additional staffing and differentiate instructional roles among educators. Small group and collaborative learning formats gain support from theories of social development and situated cognition (Brown & Campione, 1994). These models also reflect real-world work environments that rely on teams and collective problem-solving.

One alternative structure adds a teacher’s aide or co-teacher to the classroom. This model is often used for inclusion of special needs students in mainstream classes. But dual-teacher classrooms can benefit all students by allowing more individual support and targeted small group instruction. Experimental studies find the addition of a teaching assistant improves student achievement compared to solo teaching (Gerber, Finn, Achilles, & Boyd-Zaharias, 2001). Assistants can provide tutoring for struggling students, handle classroom management duties, facilitate learning activities and technology use, and relieve some pressures on the lead teacher (Blatchford et al., 2011).

Studies document how lead teachers and assistants in co-taught classrooms naturally differentiate roles based on their strengths. Lead teachers tend to focus on whole-class instruction and lesson planning while assistants circulate to monitor student work, assist with activities, and provide scaffolding for individuals (Bacharach, Heck, & Dahlberg, 2008). Some co-teaching models specifically designate the lead as the primary instructor while the assistant focuses on behavior management and academic support (Friend, 2008). This division of responsibilities allows for both efficient content delivery and targeted interventions within the same classroom.

Similarly, team teaching formats aim to reduce student-teacher ratios by having multiple educators jointly coordinate instruction. Teachers can strategically divide curriculum topics to teach in their areas of greatest expertise (Letterman & Dugan, 2004). Students benefit from exposure to different teaching styles and class discussion facilitated by two adults. Team teachers also model collaborative working relationships and collective responsibility for students' development (Buckley, 2000). Observational studies document more small group work and individual tutoring in team-taught versus solo-taught classrooms (Letterman & Dugan, 2004).

While direct comparisons of co-teaching versus team teaching are limited in the literature, both formats provide smaller student-teacher ratios than solo instruction. The critical aspect seems to be differentiating the auxiliary teacher’s role from whole-class lecturing towards more personalized guidance. Schools implementing team or co-teaching with clearly delineated responsibilities observe improvements in student learning, behavior, and teacher job satisfaction (Walther-Thomas, Bryant, & Land, 1996).

Insights from Business Management

The fields of business management and organizational behavior also yield useful insights into effective working group structures. While classroom learning differs from workplace productivity, key principles of team dynamics, group roles, and span of control may inform optimal design of teaching teams.

First, organizational studies demonstrate the advantages of small teams over large groups. Meta-analyses find that team performance on complex tasks peaks at groups of 2-15 members and declines in larger teams (Wheelan, 2009). Smaller teams enable coordination, cohesion, and equal participation from all members. Teams of around 7 members balance sufficient diversity of knowledge while minimizing coordination costs from too many relationships (Hill, 1982).

Second, certain team roles consistently emerge and prove vital to team effectiveness. Belbin’s model of team roles (1993) proposes that balanced teams need: implementers to turn ideas into action, coordinators to organize activities, shapers to guide discussions and decisions, and teamworkers to build relationships and morale. Studies validating this model confirm that higher performing teams have members that fill each role (Senior, 1997).

In a classroom setting, the lead teacher likely serves as coordinator and shaper while the teaching assistant fills implementer and teamworker roles. Effective co-teaching partnerships similarly describe how teachers naturally align with mentoring versus didactic orientations (Nellis, 2012). Combining complementary roles allows the team to maximize workflow and relational support.

Third, span of control research suggests managers can only effectively supervise a limited number of subordinates - optimally 5-8 direct reports (Vassallo, 2005). Teacher-student ratios far exceed this span, implying the need for additional supervisory support. Assistants could provide greater oversight for individual students under the lead teacher’s direction. Using teaching teams with about 15 students aligns with both pedagogical evidence on class sizes and organizational spans of control.
Proposed Model: Classrooms of 15 with Dual Teachers

Synthesizing this wide-ranging evidence leads to propose an optimal classroom organization based on:

- Class sizes of approximately 15 students, consistent with the strongest research on academic outcomes

- A lead teacher responsible for most whole-class instruction and lesson planning

- An assistant teacher providing small group, individual tutoring, behavior management, and classroom supports

- Clear differentiation of roles between lead and assistant while modeling collaborative working relationships
This model balances educational, psychological, and organizational research on effective teaching and learning environments. The small class size enables personalization and active participation identified as critical in pedagogical literature. The addition of an assistant introduces more individualized instruction and oversight demonstrated in co-teaching models. The team structure draws on principles of effective team dynamics and spans of control to maximize teachers’ complementary roles.

Of course, reducing all class sizes to 15 students would require enormous investments in staffing and facilities. But some steps in this direction could significantly improve the classroom experience. Schools might begin by implementing smaller classes and co-teaching in early elementary grades where benefits are greatest. Assistants could be added incrementally, beginning with higher needs classrooms, or by re-allocating reading and math specialist positions.

Creative scheduling could allow lead teachers to instruct two classrooms for certain academic subjects while assistants facilitate differentiated activities. Part-time paraprofessionals or floaters could also assist with certain classroom management duties. Moving towards evidence-based class sizes and teaching teams would better support both teachers and diverse 21st century learners.

Conclusion

Current educational policies that result in ever-larger class sizes undermine teachers’ ability to meet all students’ needs. Yet systemic constraints prevent widespread adoption of class size reductions. This literature review argues that, given adequate resources, creating classrooms of approximately 15 students with a lead teacher and teaching assistant can optimize conditions for learning based on interdisciplinary evidence. Further research should continue to identify creative staffing models that balance cost, feasibility, and educational effectiveness. But prioritizing smaller classes and differentiated teaching roles provides the best organizational structure available to enrich schools and help every student succeed.

Food For Thought:
 
The typical structure and ratios for teams in the US military are:

- Fire team: 4-5 soldiers led by a team leader (usually a Corporal)
- Squad: 9-10 soldiers led by a Squad Leader (usually a Sergeant)
- Platoon: 16-44 soldiers led by a Platoon Leader (usually a Lieutenant) and Platoon Sergeant (usually a Sergeant First Class)
- Company: 62-190 soldiers led by a Company Commander (usually a Captain) and First Sergeant (usually a Master Sergeant)

So at the fire team and squad level, the ratio is about 1 leader to 5 team members. At the platoon level, there are 2 leaders for every 16-44 soldiers. And at the company level leadership spans 62-190 soldiers.

The fire team of 4-5 soldiers is considered the smallest functional unit in the military, allowing for close team cohesion and supervision by the team leader. The squad combines 2-3 fire teams under a sergeant. The platoon combines several squads under officer and NCO leadership. And the company comprises several platoons and specialized staff.

So the military structure reflects an increasing span of control as you go up the hierarchy, but maintains a small team/squad ratio of about 1:5. This allows higher-level leaders to effectively manage and direct larger units through the subordinate team structure.


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