The Achievement Gap: How Demographics, Not Teaching, Drive 'Elite' School Scores

🔬The Hypothesis to Test

If "prestige" school districts like Dover-Sherborn, Weston, and Lexington have superior teaching quality, then low-income students in those districts should dramatically outperform the state average for low-income students.

Think about it: If Dover-Sherborn truly has better teachers, curriculum, and instruction, a low-income child attending those schools should benefit from that excellence and score much higher than low-income children in average districts.

The Test

This is the definitive test of instructional quality. And the results are damning.

The State Baseline

21%

Low-Income Math (MA State)

Meeting grade-level benchmarks

19%

Low-Income ELA (MA State)

Meeting grade-level benchmarks

If wealthy districts had superior instruction, low-income students in those districts should post proficiency rates of 40%, 50%, or even 60%—well above the state poverty average.

The Reality in Wealthy Districts

Cambridge Public Schools (2023 MCAS, Grade 3 ELA)

• White 3rd graders: 79% proficient\n• Black 3rd graders: 36% proficient\n• Achievement gap: 43 percentage points\n\nThis 43-point gap has widened from 37 points in 2019. Cambridge's "excellence" doesn't extend to its disadvantaged population.

Wealthy MA Districts Overall (2017-2019)

• 60% of Black children fell short of proficiency\n• 45% of Latino children fell short\n• 28% of white children fell short (baseline)\n\nSource: Boston Globe analysis

Weston Public Schools (2024 MCAS)

• Low-income students: 37% proficient (Math & ELA)\n• District average: ~75% proficient\n• Gap: 38 percentage points\n\n$2.16M median home price. $25,310 per pupil. Yet 63% of low-income students fail to meet standards.

The MIT/UMass Research

MIT-Reviewed Finding

84% of MCAS score variation across Massachusetts districts is explained by demographics, not instructional quality.\n\n— UMass Donahue Institute Analysis

The researchers were explicit: "That is why Weston and Wayland have high MCAS scores and why Holyoke and Brockton have low MCAS scores."

What This Means:

•✅ High scores in wealthy districts reflect wealthy students
•✅ Low scores in poor districts reflect poor students
•❌ Scores don't reflect teaching quality differences
•The instruction is similar. The students are different.

Why This Matters: The 'Value-Add' Question

When you're choosing a school district for your child, the question isn't "What's the average test score?" The question is: "What will this school ADD to my child's trajectory?"

Your Child	Prestige District	Value District	Outcome
Affluent & high-achieving	Will thrive	Will thrive	Identical
Average student	Will do well	Will do well	Identical
Struggling/low-income	Will struggle	Will struggle	Identical

The Data's Verdict

Prestige districts don't teach better—they SELECT better. The $700K-1.4M premium buys you an affluent peer group, not superior instruction. Your child's outcomes will be the same.

The Home Buyer's Takeaway

Achievement gaps in wealthy districts prove that high average scores reflect student demographics, not teaching excellence. When low-income students in $2M districts perform at or near state poverty averages, it confirms: the schools aren't adding value—the students are bringing it.

For Data-Driven Home Buyers:

•❌ Don't be impressed by district-wide MCAS proficiency rates
•✅ Look at Student Growth Percentiles (actual teaching effectiveness)
•✅ Look at college matriculation rates (ultimate outcomes)
•✅ Compare outcomes-per-dollar across districts
•❌ Don't pay $1M+ for demographic selection

See the Full District Comparison

Interactive data with all 9 districts analyzed

View Complete Analysis