Anderson's causal model of how reduced class size affects student achievement¶

Theory · All theories
Evidence · 5 claims (3 for, 1 mixed, 1 against) · 1 study (1 quant-synthesis), q3 · 1 of 1 report an effect size · 5 claims rest on one study

Description¶

Anderson (2000) developed a causal model explaining why class size reduction should enhance achievement, depicted in the review's Figure 1. It predicts that reduced class size has direct positive effects on three variables: "1) Disciplinary problems, 2) Knowledge of student, and 3) Teacher satisfaction and enthusiasm", each beginning a separate path. These paths converge on greater opportunity to learn, greater student engagement in learning, and more in-depth treatment of content, which jointly produce greater student achievement. The review uses the model to stress that class size influences achievement only indirectly, through what teachers and students do in the classroom.

Design Implications¶

Context¶

Requirements¶

• Class size must first influence what teachers and students do in the classroom before it can affect student learning, as the model treats class size as having only an indirect effect on achievement

Constraints¶

• The review notes teachers do not necessarily change the way they teach when faced with smaller classes, so the model's mechanisms may not operate in practice

Target Learners¶

• students in kindergarten to grade 12 general education

Target Learning Objectives¶

• academic achievement in reading and mathematics

Claims¶

• Annevelink Personalised Instruction Path Test [+M]
• Class size reduction shows a negative, statistically non-significant effect on mathematics achievement (pooled SMD ‐0.03) [-W]
• Class size reduction produces a small, statistically significant positive effect on reading achievement by end of treatment year (pooled SMD 0.11) [+W]
• All four meta-analysable STAR studies report positive, statistically significant effects of small classes, but average effects are small [+W]
• Whether timing, intensity, and duration of class size reduction moderate its effect remains an open question in the literature the review synthesises [~W]

Related Theories¶

Examples¶

-

Key Sources¶

• Filges, T., Sonne‐Schmidt, C. S., Nielsen, B. C. V. (2018). Small class sizes for improving student achievement in primary and secondary schools: a systematic review. Campbell Systematic Reviews 2018:10. https://doi.org/10.4073/csr.2018.10