- Enrollment
- 2,620
- Students per teacher
- 12.5:1
- Resource Index
- 54/100
Elementary school (grades K-5) · Cos Cob, CT
Cos Cob School
Federal NCES profile for Cos Cob School, including enrollment, faculty, free-lunch eligibility, demographics, and resource indicators - Resource Investment Index 60/100.
2024-25 NCES dataElementary school (grades K-5)NCES 090171000296
👥 S:T ratio 63
🌟 Gifted program 70
🎓 Counselors 31
📋 Attendance 75
Scored 0–100 from federal NCES and CRDC indicators, resource allocation, not test scores. Full methodology →
The verdict
Cos Cob School earns 60/100 on the Resource Investment Index, with class sizes smaller than 87% of Connecticut schools.
- 60
- Resource Index · Higher
- 9.3:1
- small classes for Connecticut
- 11.6%
- free-lunch eligible
- 343
- students enrolled
Cos Cob School has class sizes smaller than 87% of Connecticut schools. Computed live against every Connecticut school reporting to NCES.
School address
District: Greenwich School District · Connecticut
NCES ID 090171000296 Verify on NCES CCD record →
CCD year-over-year · 2022-23 → 2023-24
+3 students YoY
Cos Cob School held near 340 students from 2022-23 to 2023-24 (+3 headcount).
Teacher FTE lost 37.8 → 35.9 across the same CCD years.
Source: NCES Common Core of Data public-school universe (2022-23, 2023-24).
Steady CCD campus
+3 students YoY 090171000296 · Cos Cob, CT Elementary · SMALL · TRAD
343 enr · 9.3:1 · 11.6% lunch · RII 60
Nearest enrollment peer: Greenwich High School (2,620 students)
Cos Cob School held near 340 students from 2022-23 to 2023-24 (+3 headcount). Teacher FTE lost 37.8 → 35.9 across the same CCD years. Read with this school → · District book → · Connecticut schools → · Find another →
Cos Cob School in the enrollment neighbourhood
Fall enrollment among this campus and nearest district peers
- Greenwich High
Greenwich High School
2,620 students
- Eastern Middle 797
Eastern Middle School
797 students
- Western Middle 563
Western Middle School
563 students
- Central Middle 483
Central Middle School
483 students
- Riverside Scho 440
Riverside School
440 students
- This school 343
Cos Cob School
343 students
What this shows Cos Cob School reports 343 students on the CCD universe file.
How Cos Cob School compares
Cos Cob School held steady on CCD headcount: ratios and free-lunch share vs Connecticut and U.S. means.
| Metric | This school | vs Connecticut | Connecticut avg | U.S. avg |
|---|---|---|---|---|
| Students per teacher | 9.3:1 | ▼ 23% | 12.1:1 | 15.7:1 |
| Free-lunch eligible | 11.6% | ▼ 68% | 36.4% | 51.7% |
| Enrollment | 343 | top 65% | - | - |
Source: NCES Common Core of Data School-level CCD + state/national means from Public School Universe · 2024-25
9.3:1
Leaner classes than 92% of US schools, among the more generously staffed nationally.
343
Bigger than 39% of US schools by enrollment, mid-sized for the country.
Equity indicators methodology
Economic need
11.6%
free-lunch eligible
- 68% below the Connecticut average of 36.4%
Below the 40% Title I threshold, among the lower-need profiles in the state; federal aid targets individual qualifying students rather than schoolwide programs.
Staffing depth
9.3:1
students per teacher
- 23% below state mean
Top 13% in Connecticut - lower ratio than 87% of state schools
Well under the widely cited 15:1 individualized-attention benchmark, among the leaner class loads nationally.
Engagement
10.2%
chronically absent (missed 10%+ of school days)
In the 10-15% range, above the pre-pandemic national baseline but within the broader post-pandemic picture.
Funding equity
$31,154
per pupil, district-wide
- above Connecticut avg of $24,680
Well above the U.S. public-school average, reflecting substantially higher local or state investment per enrolled student.
Support staff
Counselors1.0 FTE
Per 343 students, the combined health-and-guidance staffing load for this school.
Discipline context
0
in-school suspensions + 0 out-of-school
Suspension rate: 0.0 per 100 students. Combined in-school and out-of-school rate: 0.0 per 100 students. Reported via the Civil Rights Data Collection.
Student demographics
White 67.3%
Hispanic or Latino 20.4%
Asian 5.2%
Two or More 5.2%
African American 1.2%
American Indian / Alaska Native 0.6%
Largest group: White at 67.3% of enrollment.
Student-body diversity index 50.0/100
Simpson diversity index - at 50.0, Cos Cob School is about as mixed as the Connecticut school average of 50.5.
Programs
Gifted & talented Yes
District finance for Greenwich School District reports $31,154 per pupil (NCES F-33) - open the district page for the full revenue mix.
How Cos Cob School Compares to District-Mates
| School | Enrollment | Economic Profile | Student-Teacher Ratio |
|---|---|---|---|
| Greenwich High School | Larger | Similar economic need | Higher S:T ratio |
| Eastern Middle School | Larger | Similar economic need | Similar S:T ratio |
| Western Middle School | Larger | Higher economic need | Similar S:T ratio |
| Central Middle School | Larger | Similar economic need | Similar S:T ratio |
| Riverside School | Larger | Similar economic need | Higher S:T ratio |
Comparisons are relative to Cos Cob School's own figures; each column derives from NCES Common Core of Data.
Other Schools in This District
- Enrollment
- 797
- Students per teacher
- 10.4:1
- Resource Index
- 66/100
- Enrollment
- 563
- Students per teacher
- 8.3:1
- Resource Index
- 67/100
- Enrollment
- 483
- Students per teacher
- 8.8:1
- Resource Index
- 65/100
- Enrollment
- 440
- Students per teacher
- 12.6:1
- Resource Index
- 68/100
Nationwide elementary schools with similar size or staffing
Out-of-state peers matched by enrollment and by student-teacher ratio, not the same-city or same-district lists above.
Similar enrollment (~343 students)
Frequently asked questions about Cos Cob School
How many students attend Cos Cob School?
Cos Cob School has 343 students enrolled. It is an elementary school in Cos Cob, CT. CCD year-over-year: 337 (2022-23) → 340 (2023-24), nearly flat (+3).
What is the student-teacher ratio at Cos Cob School?
The student-teacher ratio at Cos Cob School is 9.3:1, which is 23% lower than the Connecticut average of 12.1:1 and 41% lower than the national average of 15.7:1. Lower ratios generally mean more individual attention per student.
What percentage of students receive free lunch at Cos Cob School?
11.6% of students at Cos Cob School are eligible for free lunch, compared to the Connecticut average of 36.4%.
What is the racial and ethnic makeup of Cos Cob School?
The largest demographic group at Cos Cob School is White at 67.3% of enrollment, in Cos Cob, CT. Its student body is more racially and ethnically mixed than most US schools, with a diversity index of 50.0/100.
What is the Resource Investment Index for Cos Cob School?
Cos Cob School has a Resource Investment Index of 60/100 (higher reported resources relative to schools nationally) based on 4 factors: student-teacher ratio, gifted-program reporting, counselor availability, chronic absenteeism. Not a test-score or academic measure (national median ~41/100, see methodology).
What other schools are in Greenwich School District?
Besides Cos Cob School, Greenwich School District also operates Greenwich High School (2,620 students), Eastern Middle School (797 students), and Western Middle School (563 students). See the Greenwich School District district page for the complete list.