Enrollment
525
New York · 2024-25 NCES data
2024-25 NCES data Other / mixed grade configuration NCES 362820003810
William Sidney Mount Elementary School — Stony Brook, NY
Federal NCES profile for William Sidney Mount Elementary School, including enrollment, faculty, free-lunch eligibility, demographics, and resource indicators — Resource Investment Index 53/100.
👥 Class size 50
🌟 Gifted program 30
📋 Attendance 80
How this works: Each indicator above is scored 0–100 from federal NCES and CRDC data, then averaged into the Resource Investment Index. This measures resource allocation — staffing, programs, and support services — not standardized test scores or academic outcomes. Full methodology →
The verdict
William Sidney Mount Elementary School earns a C- Resource Investment Index (53/100), with class sizes near the New York median.
- C-
- Resource Index · 53/100
- 12.5:1
- students per teacher
- 16.6%
- free-lunch eligible
- 525
- students enrolled
School address
District: Three Village Central School District · New York
Public location data per NCES (National Center for Education Statistics) Common Core of Data. Verify the school's current address on the NCES CCD record.
Teachers (FTE)
41.0
Federal CCD staff survey
Students per teacher
12.5:1
vs 11.7:1 New York avg
+7% vs state
Free-lunch eligible
16.6%
vs 56.2% New York avg
-70% vs state
Student-teacher ratio in context
How William Sidney Mount Elementary School compares with New York and U.S. medians
The federal record — no proprietary index, no editorial formula.
PlainSchools publishes the actual federal measurements — enrollment, staffing, demographics, discipline, and finance — straight from the NCES Common Core of Data, CRDC, and F-33 surveys. No composite rating, no opinion-based score on top. You get the same raw numbers researchers and policymakers use, with benchmarks, spending context, and equity indicators computed from the same federal datasets. Full methodology linked below.
What this school's NCES data tells you
William Sidney Mount Elementary School reports 525 enrolled students to the National Center for Education Statistics (NCES) alongside 41.0 full-time-equivalent teachers, producing a 12.5:1 student-teacher ratio. That figure sits 7% above the New York state mean of 11.7:1, signalling larger average class loads than peers in the same state. Against the national 2024-25 average of 15.7:1, it is 20% lower, a useful calibration for families comparing districts across state lines.
Title I and federal lunch eligibility offer another window into the student body: 16.6% of pupils qualify for free meals, a proxy for household income that federal programs use to direct funding. The free-lunch share is 70% below the New York average and 68% below the national baseline. Chronic absenteeism — missing 10% or more of school days — stands at 8.0% according to the 2021-22 Civil Rights Data Collection.
On the finance side, the surrounding Three Village Central School District spends $36,330 per pupil district-wide, above the New York average of $26,410 and above the national average of $16,593. Revenue comes 71.7% from local sources (property taxes), 25.5% from the state, and 2.8% from federal programs per the NCES F-33 finance survey. Taken together, these measurements produce a Resource Investment Index of 53/100 (C-), calculated from 3 distinct NCES and CRDC indicators measuring resource allocation rather than academic outcomes.
Source: National Center for Education Statistics Common Core of Data + CRDC + F-33 · 2024-25
How William Sidney Mount Elementary School compares
Cross-validating school-level NCES values against New York state and U.S. national means lets readers see whether this school is an outlier or in line with peers.
| Metric | This school | vs New York | New York avg | U.S. avg |
|---|---|---|---|---|
| Students per teacher | 12.5:1 | ▲ 7% | 11.7:1 | 15.7:1 |
| Free-lunch eligible | 16.6% | ▼ 70% | 56.2% | 51.8% |
| Enrollment | 525 | top 66% | — | — |
Source: NCES Common Core of Data School-level CCD + state/national means from Public School Universe · 2024-25
Class size vs. every US school
Students per teacher (lower means more individual attention)
13 Among the smallest classes smaller classes than 74% of 92,598 US schools
Each bar is a band; taller bars hold more US schools. The dashed line + filled bar mark this entry. Hover or tap any bar for its full count, share, and where it sits relative to this entry.
Source U.S. Department of Education — NCES Common Core of Data · 2024-25
School size vs. every US school
Total enrollment — where this school sits by size (neither large nor small is 'better')
525 larger than 65% of 95,891 US schools
Each bar is a band; taller bars hold more US schools. The dashed line + filled bar mark this entry. Hover or tap any bar for its full count, share, and where it sits relative to this entry.
Source U.S. Department of Education — NCES Common Core of Data · 2024-25
What the federal data reveals about equity at this school
Federal measurements — not ratings — surface the resource and opportunity picture. Below are the indicators that researchers, civil-rights monitors, and funding formulas use to assess equity.
Economic need
16.6%
free-lunch eligible
— 70% below the New York average of 56.2%
Below the 40% Title I threshold — federal aid targets individual qualifying students rather than schoolwide programs.
Staffing depth
12.5:1
students per teacher
— 7% above state mean
Top 66% in New York — lower ratio than 34% of state schools
Below the 15:1 benchmark — typical of schools with smaller class sizes and more individualized attention.
Engagement
8.0%
chronically absent (missed 10%+ of school days)
Below 10% — strong attendance relative to the post-pandemic national landscape.
Funding equity
$36,330
per pupil, district-wide
— above New York avg of $26,410
Above the U.S. public-school average, reflecting higher local or state investment per enrolled student.
Support staff
Counselors0.0 FTE
Student-support staffing from the Civil Rights Data Collection.
Discipline context
2
in-school suspensions + 0 out-of-school
Suspension rate: 0.4 per 100 students. Combined in-school and out-of-school rate: 0.4 per 100 students. Reported via the Civil Rights Data Collection.
Overview
Enrollment 525 Top 66% in New York — larger than 34% of 4,812 state schools
Teachers (FTE) 41.0
Students per teacher 12.5:1 +7% vs state
Free-lunch eligible 16.6% -70% vs state
NCES ID 362820003810
Student demographics
White 55.0%
Asian 24.4%
Hispanic or Latino 14.1%
Two or More 5.3%
African American 1.1%
Largest group: White at 55.0% of enrollment.
Programs & staff
Counselors (FTE) 0.0
Discipline & special education
Chronically absent 8.0%
In-school suspensions 2
Out-of-school suspensions 0
Funding & spending
District-wide per-pupil expenditure for Three Village Central School District, which includes William Sidney Mount Elementary School.
$36,330
Per student
+38%
vs New York
Avg $26,410
+119%
vs U.S.
Avg $16,593
Revenue mix
Local 71.7%
State 25.5%
Federal 2.8%
Source: NCES F-33 School District Finance Survey District-level finance · FY 2021-22 Per-pupil expenditure reflects the district-wide average. Individual school budgets are not reported at the federal level.
Other Schools in This District
- Enrollment
- 1,442
- Students per teacher
- 10.8:1
- Enrollment
- 655
- Students per teacher
- 10.4:1
- Enrollment
- 651
- Students per teacher
- 10.8:1
- Enrollment
- 644
- Students per teacher
- 14:1
- Enrollment
- 599
- Students per teacher
- 11.8:1
Educator & family resources
In-depth guides on understanding NCES data, school choice, and education funding.
Understanding NCES data
How CCD, CRDC and EDFacts feed every public-school number you see.
Choose a school district
Eight signals that matter more than the overall ranking number.
How schools are funded
Title I, F-33, state aid formulas and what per-pupil spending really means.
Chronic absenteeism
Why missing 10% of school matters and how it varies by district.
Magnet vs charter vs traditional
Three school types, three funding models, three sets of trade-offs.
School discipline data
What CRDC suspension and expulsion records do and don't reveal.
Frequently asked questions about William Sidney Mount Elementary School
How many students attend William Sidney Mount Elementary School?
William Sidney Mount Elementary School has 525 students enrolled. It is a other school in Stony Brook, NY.
What is the student-teacher ratio at William Sidney Mount Elementary School?
The student-teacher ratio at William Sidney Mount Elementary School is 12.5:1, which is 7% higher than the New York average of 11.7:1 and 20% lower than the national average of 15.7:1.
What percentage of students receive free lunch at William Sidney Mount Elementary School?
16.6% of students at William Sidney Mount Elementary School are eligible for free lunch, compared to the New York average of 56.2%.
What is the racial and ethnic makeup of William Sidney Mount Elementary School?
The largest demographic group at William Sidney Mount Elementary School is White at 55.0%. The school serves a diverse student body in Stony Brook, NY.
What is the Resource Investment Index for William Sidney Mount Elementary School?
William Sidney Mount Elementary School has a Resource Investment Index of 53/100 (C-) based on 3 factors: student-teacher ratio, attendance rates. This index measures federal resource allocation — staffing levels, program availability, and support services — not standardized test scores or academic outcomes.
Is William Sidney Mount Elementary School a good school?
William Sidney Mount Elementary School earns a C- Resource Investment Index (53/100), with class sizes near the New York median. The Resource Investment Index reflects staffing, counselor access, gifted programs, and attendance reported to NCES, not test scores or academic outcomes, so treat it as a resource snapshot rather than an overall rating.