A+
Excellent
96/100

William Sidney Mount Elementary School

📚 Pre-K – 06 🏫 School
📍 50 DEAN LN, Stony Brook, NY 11790
Overall
A+
96/100 · the blend of everything below
Achievement
A+
Reading 67% · Math 77% proficient · 91st percentile in New York
Resources
A+
Class size, funding, school size and type

📚 Top 15% in New York for achievement

Each score is graded separately against New York schools. A school can be strong at moving students forward (growth) without having the highest test scores, or the reverse. How we score schools

96
Repit Score
out of 100
514
Students
enrolled
13.6:1
Student:Teacher
ratio
$38K
Per Student
spending

What Goes Into This Rating

FactorWeightScoreBasis
📚 Academics (reading & math)75%91/100reading 89th percentile, math 92nd percentile among New York middle schools (2018–19 state tests)
🏫 Resources (class size, funding, size, type)25%96/100Inputs from NCES school and district data

Students served: 20% students eligible for free or reduced-price lunch. Compared with New York schools serving a similar share of low-income students, this school’s reading and math results are +15 points better than expected. (Context only; not part of the score.)

The overall Repit Score ranks this blend against every rated school in New York. Schools are compared within their state because each state sets its own tests and proficiency bar. How we rate schools

Test Scores & Graduation

📖 Reading proficiency67% (+11 pts vs. state avg 56%)
Students scoring proficient on the state test, 2018–19
➗ Math proficiency77% (+20 pts vs. state avg 57%)
Students scoring proficient on the state test, 2018–19

Source: U.S. Department of Education EDFacts via the Urban Institute Education Data Portal. Federal reporting rounds small schools to ranges; we show the midpoint. Proficiency standards differ by state, so compare schools within the same state.

How Student Groups Do Here

Share of each group of students scoring proficient on the New York state test (2018–19), compared with the same group of students across the state. Differences between groups are shown as reported; they reflect many factors inside and outside school.

StudentsReadingMathvs. same group statewideRank in state for this group
White65%75%reading +13 pts, math +17 pts83rd percentile (list)
Asian75%85%reading +6 pts, math +11 pts73rd percentile (list)
Low-income—70%math +36 pts97th percentile (list)

Source: U.S. Department of Education EDFacts via the Urban Institute. Groups with fewer than 20 tested students are not shown. Results are achievement (proficiency), not growth; growth by group is not published for individual schools.

School Information

Address 50 DEAN LN
City Stony Brook
ZIP Code 11790
District 3628200
NCES School ID 362820003810
Data Year 2024-25

Community Context for 11790

Understanding the community around William Sidney Mount Elementary School helps evaluate the school environment and neighborhood.

💰 Income & Economy

Median Household Income $145,545
Per Capita Income $48,293
Poverty Rate 0.7%
Households Earning $100K+ 71.1%

🎓 Education Level

Bachelor's Degree or Higher 67.3%
High School or Higher 98.8%

🏠 Housing

Median Home Value $579,700
Median Rent $2,836
Owner-Occupied 89.2%
Renter-Occupied 10.8%
View full data for ZIP 11790 →

Thinking about moving into this school’s area? See what homes and rents actually cost in ZIP 11790 — values, rent, and how it compares to nearby ZIPs. Free, no signup. See 11790 housing costs →

Student Demographics

Enrollment and demographic breakdown for William Sidney Mount Elementary School.

👫 Gender Distribution

Male 50.8%
Female 49.2%

🌎 Race & Ethnicity

White 56.8%
Asian 23.7%
Hispanic/Latino 12.8%
Two or More Races 5.1%
Black 1.6%

📋 Enrollment Summary

Total Enrollment 514
Teachers (FTE) 37.8
Student:Teacher Ratio 13.6:1

Frequently Asked Questions

What is the Repit School Score for William Sidney Mount Elementary School?
William Sidney Mount Elementary School has a Repit School Score of 96 out of 100, earning a grade of A+. The score is based mainly on reading and math proficiency compared with other schools in the state, with class size and funding counting for a smaller share.
How many students attend William Sidney Mount Elementary School?
William Sidney Mount Elementary School has 514 students enrolled for the 2024-25 school year. The student-to-teacher ratio is 13.6:1.
What grades does William Sidney Mount Elementary School serve?
William Sidney Mount Elementary School serves grades Pre-K – 06 and is classified as a School. This is a public school.
How much funding does William Sidney Mount Elementary School receive per student?
William Sidney Mount Elementary School receives $37,856 in per-pupil spending from its district. This is above the national average.
🏠 Rental Market Around William Sidney Mount Elementary School in 11790 ▼
Avg Home Value
$797,463
Avg Monthly Rent
$4,621
1-Year Change
+9.1%
% Renters
10.8%

Other Schools in 11790

View all schools and real estate data for 11790 →

About Repit School Scores

Parents choosing a school deserve to see what it actually delivers. Since October 2026 the Repit School Score is built mainly on results:

  • Academics (largest share) — the share of students scoring proficient in reading and math on the state test, ranked against schools of the same level in the same state.
  • Graduation (high schools) — the four-year adjusted cohort graduation rate. Only regular diplomas count; GEDs and certificates of attendance do not.
  • Resources (smaller share) — class size, per-pupil funding, school size and type.

Scores compare schools within their own state, because every state writes its own tests and sets its own proficiency bar. Full methodology

Data sources: NCES CCD 2024-25, U.S. Dept. of Education EDFacts (test results & graduation) | Last updated: October 2026