Enrollment
123
Arizona · 2024-25 NCES data
Elementary school (grades K-5) · Casa Grande, AZ
Mary C O'brien Elementary School
Federal NCES profile for Mary C O'brien Elementary School, including enrollment, faculty, free-lunch eligibility, demographics, and resource indicators - Resource Investment Index 42/100.
2024-25 NCES dataElementary school (grades K-5)NCES 040274000203
👥 S:T ratio 55
🌟 Gifted program 70
📋 Attendance 0
Scored 0–100 from federal NCES and CRDC indicators, resource allocation, not test scores. Full methodology →
The verdict
Mary C O'brien Elementary School earns 42/100 on the Resource Investment Index, with class sizes smaller than 88% of Arizona schools.
- #2 of 3
- elementary schools in Casa Grande · Resource Index
- 42
- Resource Index · Typical
- 11.2:1
- small classes for Arizona
- 51.7%
- free-lunch eligible
Mary C O'brien Elementary School has class sizes smaller than 88% of Arizona schools. Computed live against every Arizona school reporting to NCES.
By Resource Investment Index, Mary C O'brien Elementary School ranks #2 of 3 elementary schools in Casa Grande, AZ.
School address
District: Mary C O'brien Accommodation District (4435) · Arizona
NCES ID 040274000203 Verify on NCES CCD record →
Teachers (FTE)
11.0
Federal CCD staff survey
Students per teacher
11.2:1
vs 17:1 Arizona avg
-34% vs state
Free-lunch eligible
51.7%
vs 48.3% Arizona avg
+7% vs state
Student-teacher ratio in context
How Mary C O'brien Elementary School compares with Arizona and U.S. medians
What stands out at Mary C O'brien Elementary School
Mary C O'brien Elementary School is a higher-need, mid-sized elementary school in Casa Grande, Arizona, enrolling 123 students.
Classes run notably small here: at 11.2:1, Mary C O'brien Elementary School is leaner than roughly 88% of Arizona schools and 34% under the state's 17:1 norm, more adult attention per pupil than most peers.
Its free-meal eligibility rate of 51.7% lands close to the Arizona typical range, neither a high- nor low-need campus by this measure.
Enrollment of 123 puts it in the smaller third of Arizona schools by headcount.
Its Resource Investment Index lands in the upper third of 2,064 scored Arizona schools.
Against 76 statewide peers matched on enrollment and economic need, it ranks in the upper tier at #26.
Its student body is led by Hispanic or Latino (53%) and White (37%) (diversity index 58/100).
Chronic absenteeism is elevated: 45.5% of students missed 10% or more of school days (2021-22 Civil Rights Data Collection).
The surrounding Mary C O'brien Accommodation District (4435) spends $26,564 per pupil, 102% above the Arizona average, a better-resourced district than most.
Among Casa Grande's elementary schools, it stands alongside Legacy Traditional School - Casa Grande (1,486 students): Mary C O'brien Elementary School is smaller than that campus by headcount.
Its district, Mary C O'brien Accommodation District (4435), also runs Villa Oasis Interscholastic Center for Education (Voice) (75 students).
Sourced from NCES CCD, CRDC, and F-33 (federal records, not a quality verdict). How we source and compute this.
Source: National Center for Education Statistics Common Core of Data + CRDC + F-33 · 2024-25
How Mary C O'brien Elementary School compares
Mary C O'brien Elementary School on the metrics families compare, against Arizona and U.S. means.
| Metric | This school | vs Arizona | Arizona avg | U.S. avg |
|---|---|---|---|---|
| Students per teacher | 11.2:1 | ▼ 34% | 17:1 | 15.7:1 |
| Free-lunch eligible | 51.7% | ▲ 7% | 48.3% | 51.7% |
| Enrollment | 123 | top 80% | - | - |
Source: NCES Common Core of Data School-level CCD + state/national means from Public School Universe · 2024-25
11.2:1
Leaner classes than 82% of US schools, among the more generously staffed nationally.
123
Bigger than 12% of US schools by enrollment, a small campus.
Equity indicators (what these measure)
Economic need
51.7%
free-lunch eligible
- 7% above the Arizona average of 48.3%
Above the 40% Title I schoolwide threshold; federal funds support the whole school, not individual students.
Staffing depth
11.2:1
students per teacher
- 34% below state mean
Top 12% in Arizona - lower ratio than 88% of state schools
Well under the widely cited 15:1 individualized-attention benchmark, among the leaner class loads nationally.
Engagement
45.5%
chronically absent (missed 10%+ of school days)
At or above 20%, the commonly used threshold for "high" chronic absenteeism, signaling significant barriers to regular attendance.
Funding equity
$26,564
per pupil, district-wide
- above Arizona avg of $13,145
Well above the U.S. public-school average, reflecting substantially higher local or state investment per enrolled student.
Support staff
Counselors0.0 FTE
Student-support staffing from the Civil Rights Data Collection.
Discipline context
1
in-school suspensions + 1 out-of-school
Suspension rate: 0.8 per 100 students. Combined in-school and out-of-school rate: 1.6 per 100 students. Reported via the Civil Rights Data Collection.
Overview
- Common Core of Data (June 2026): enrollment, staffing, and the student-teacher ratio above.
- Civil Rights Data Collection: discipline counts and program access (AP, gifted, special education).
- F-33 School District Finance Survey: the district-wide per-pupil spending figures below.
Three separate federal collections, each on its own reporting cadence - which is why this school's numbers line up on a consistent basis against every other school and state on this site, rather than mixing figures pulled from different survey years.
Student demographics
Hispanic or Latino 52.8%
White 36.6%
Two or More 7.3%
American Indian / Alaska Native 2.4%
African American 0.8%
Largest group: Hispanic or Latino at 52.8% of enrollment.
Student-body diversity index 58.1/100
Simpson diversity index - at 58.1, Mary C O'brien Elementary School is more mixed than the Arizona school average of 47.2.
Programs
Gifted & talented Yes
Funding & spending
District-wide per-pupil expenditure for Mary C O'brien Accommodation District (4435), which includes Mary C O'brien Elementary School.
$26,564
Per student
+102%
vs Arizona
Avg $13,145
+60%
vs U.S.
Avg $16,593
Revenue mix
Local 57.3%
State 30.7%
Federal 12.1%
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.
How Mary C O'brien Elementary School Compares to District-Mates
| School | Enrollment | Economic Profile | Student-Teacher Ratio |
|---|---|---|---|
| Villa Oasis Interscholastic Center for Education (Voice) | Smaller | Similar economic need | Lower S:T ratio |
Comparisons are relative to Mary C O'brien Elementary School's own figures; each column derives from NCES Common Core of Data.
Other Schools in This District
- Enrollment
- 75
- Students per teacher
- 8.3:1
- Resource Index
- 61/100
Similar elementary schools in Casa Grande
1 comparable elementary schools (grades K-5) serving the same city.
Similar elementary schools statewide
Matched by enrollment size and by staffing ratio across all of Arizona, not just this city - a different peer set than the local comparisons above.
Similar enrollment (~123 students)
Similar student-teacher ratio (~11.2:1)
Next steps
Verify locally before acting on Mary C O'brien Elementary School's federal record.
- Compare Mary C O'brien Elementary School against another school. Compare schools
- Mary C O'brien Accommodation District (4435)'s spending and staffing shape this school. District profile
- Confirm current enrollment and boundaries with the school. Choosing guide
Federal record (CCD 2024-25, CRDC 2021-22) - PlainSchools assigns no subjective rating; the composite quality score is a transparent, reproducible index computed from this cited federal data.
Frequently asked questions about Mary C O'brien Elementary School
How many students attend Mary C O'brien Elementary School?
Mary C O'brien Elementary School has 123 students enrolled. It is an elementary school in Casa Grande, AZ.
What is the student-teacher ratio at Mary C O'brien Elementary School?
The student-teacher ratio at Mary C O'brien Elementary School is 11.2:1, which is 34% lower than the Arizona average of 17:1 and 29% 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 Mary C O'brien Elementary School?
51.7% of students at Mary C O'brien Elementary School are eligible for free lunch, compared to the Arizona average of 48.3%.
What is the racial and ethnic makeup of Mary C O'brien Elementary School?
The largest demographic group at Mary C O'brien Elementary School is Hispanic or Latino at 52.8% of enrollment, in Casa Grande, AZ. Its student body is more racially and ethnically mixed than most US schools, with a diversity index of 58.1/100.
What is the Resource Investment Index for Mary C O'brien Elementary School?
Mary C O'brien Elementary School has a Resource Investment Index of 42/100 (typical reported resources relative to schools nationally) based on 3 factors: student-teacher ratio, attendance rates. Not a test-score or academic measure (national median ~41/100, see methodology).
How does Mary C O'brien Elementary School rank among elementary schools in Casa Grande?
By Resource Investment Index, Mary C O'brien Elementary School ranks #2 of 3 elementary schools in Casa Grande, AZ. This compares federal resource and staffing data among local peers; it is not a test-score or academic ranking. See all elementary schools in Casa Grande on the city page.
Is Mary C O'brien Elementary School a good school?
Mary C O'brien Elementary School earns 42/100 on the Resource Investment Index, with class sizes smaller than 88% of Arizona schools. This is a resource snapshot, not an academic rating; see the Resource Investment Index question above for what the number does and doesn't measure.
What other schools are in Mary C O'brien Accommodation District (4435)?
Besides Mary C O'brien Elementary School, Mary C O'brien Accommodation District (4435) also operates Villa Oasis Interscholastic Center for Education (Voice) (75 students). See the Mary C O'brien Accommodation District (4435) district page for the complete list.
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Every figure on PlainSchools is rendered directly from the source NCES, CRDC and F-33 federal records, no number is typed in by an editor. Each school's figures reflect its most recent NCES/CRDC submission on file. See our editorial standards & corrections policy, the methodology behind these numbers, or report a data error. Data current as of June 2026.