Fish pond effects: above-norm students became more likely to fail algebra when their skills were low relative to classroom peers after sorting¶

Claim · All claims
Evidence · 1 study · causal r2 · q3
Currency · newest study 2013 · checked against its sources 2026-10-20 (automated, 1 of 1 entry) · not reviewed by a person

Subclaims¶

q3 i? The likelihood of passing decreases if students have substantially lower initial skills than their classroom peers (coefficient of –.25), while it increases if students have stronger skills than classmates (coefficient of .28). → Takako Nomi and Elaine M. Allensworth 2013

Evidence¶

Takako Nomi and Elaine M. Allensworth 2013¶

Takako Nomi and Elaine M. Allensworth. (2013). Sorting and Supporting: Why Double-Dose Algebra Led to Better Test Scores but More Course Failures. American Educational Research Journal. https://doi.org/10.3102/0002831212469997

q3 · i? · causal · r2

Logistic models predicting algebra pass rates for above-norm students post-policy. "The likelihood of passing decreases if students have substantially lower initial skills than their classroom peers" — the fish pond effect. The decline in pass rates shrinks from –.24 to –.14 logits and is no longer significant after controlling for relative skills.

"The likelihood of passing decreases if students have substantially lower initial skills than their classroom peers (coefficient of –.25), while the likelihood of passing increases if students have stronger skills than their classmates (coefficient of .28)."

Discussion¶

Related Claims¶

• Below-norm students' pass rates improved post-policy because their skills relative to classroom peers improved under sorting — related
• The double-dose algebra policy adversely affected non-targeted above-norm students: their algebra grades declined and failure rates increased post-policy — related
• Algebra failure rates rose post-policy for above-norm students (~3 percentage points) but fell for below-norm students (~4 points); classroom environment and peer ability explained most of the above-norm rise but not the below-norm fall — related
• Classroom peer skill levels explain about 20% of post-policy test score improvements among above-norm algebra students in Chicago — related
• Failure rates increased and grades declined for higher-skill students in single-period algebra after the policy — related
• Double-dose algebra support courses improved algebra test scores for targeted low-skilled students but only modestly affected grades and failure rates — related
• How students are sorted into classrooms by skill level can affect their achievement as much as the content they are taught — a broader claim this one bears on
• Sorting by ability affects grades and pass rates differently from test scores: high-skilled students' grades and pass rates decline while low-skilled students' grades improve — related
• Average test scores are higher when classes are sorted by skill, driven by large learning gains for high-skilled students and slightly lower scores for low-skilled students — related
• When classes are sorted by skill level, low-skilled students are at higher risk of being in disruptive classrooms, weakening their instructional environment — related
• Average course-specific test scores decrease as grade level increases, reflecting ability self-selection — related