Is it real?
Yes. Never revoked by the IRS. Latest filing on record: FY2025. IRS ruling in May 2014.
IRS Pub. 78 · IRS Auto-Revocation List · IRS Business Master File
Where the money goes
90 cents of each dollar spent went to programs.
Form 990 Part IX, line 25, columns B–D. Every line is in By the numbers.
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Who runs it and what they're paid
13 people listed on the 990; $693K paid to officers and key staff.
Samuel Vandervelde’s $268K as Head of School is at the 57th percentile of top reported officer pay among 3683 $10–100M education nonprofits. Peer set: organizations in the same NTEE major field of work and revenue-size band, compared on each org’s own highest-paid officer/key-employee, from Form 990 Part VII / 990-PF Part VIII. Descriptive placement, not a verdict on whether the pay is appropriate.
Compensation history total reportable pay by year · 8 named individuals · Part VII
| Name | FY2025 | FY2024 | FY2023 | FY2022 | FY2021 | FY2020 |
|---|---|---|---|---|---|---|
| Samuel Vandervelde | $267,945 | $250,853 | $244,080 | $236,178 | — | — |
| Kathy Lin | $253,120 | $234,360 | $219,974 | $210,846 | $199,063 | $189,051 |
| Zachary Sifuentes | $242,597 | $223,153 | $210,489 | $201,981 | $191,331 | $183,316 |
| Samuel K Vandervelde | — | — | — | — | $225,899 | $219,773 |
| Jason Horowitz | $124,168 | $114,878 | $106,245 | $105,614 | $102,092 | $101,098 |
| Susan Durst | $122,671 | $111,833 | $103,917 | $103,917 | — | — |
| Connie You | $114,657 | $100,470 | — | — | — | — |
| Michael Yetman | $111,605 | — | — | — | — | — |
Total reportable compensation (Form 990 Part VII column D / Schedule J column E) by filing year, matched by name within this organization. The Schedule J base / bonus / deferred breakdown is not parsed into this dataset.
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Questions the 990 asks
The form asks each of these directly. These are the filed answers.
- Family or business ties among officersPt VI · Ln 2No
- Top official's pay set by an independent reviewPt VI · Ln 15aYes
Programs and updates
Educates children who love math, reasoning, and communication with a liberal arts approach.
Questions for Proof School
Your first name shows with your question. Proof School answers here, for everyone.
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Proof school delivered a comprehensive middle or high school curriculum to a total of 111 students during the 2019-20 academic year. School was in session for 172 days; the school also held two symposiums, two info sessions, one math festivals, and graduated 11 students.
Funders
Who pays for it.
From grant filings on record. Receipts are incomplete: individual donors are never listed.
Grants
By the numbers
The FY2020 990, line by line.
Download 990
| Line | Start FY20 | End FY20 |
|---|---|---|
| Cash and savingsLn 1–2 | $1.5M | $2.2M |
| InvestmentsLn 11–13 | $551K | $611K |
| Land, buildings, equipmentLn 10c | $2.3M | $2.2M |
| Total assetsLn 16 | $7.0M | $7.8M |
| LiabilitiesLn 26 | $4.3M | $4.7M |
| Net assetsLn 32 | $2.7M | $3.1M |
| Line | Total | Programs | Management | Fundraising |
|---|---|---|---|---|
| Grants to domestic individualsLn 2 | $1.1M | $1.1M | ||
| Pay of current officers, directors and key staffLn 5 | $688K | $688K | ||
| Other salaries and wagesLn 7 | $1.4M | $1.3M | $148K | |
| Other employee benefitsLn 9 | $201K | $174K | $27K | |
| Payroll taxesLn 10 | $146K | $134K | $12K | |
| Accounting feesLn 11c | $15K | $12K | $4K | |
| Advertising and promotionLn 12 | $154 | $154 | ||
| Office expensesLn 13 | $19K | $11K | $6K | $1K |
| Information technologyLn 14 | $28K | $22K | $7K | |
| OccupancyLn 16 | $880K | $690K | $190K | |
| TravelLn 17 | $6K | $6K | ||
| Depreciation, depletion and amortizationLn 22 | $283K | $221K | $62K | |
| InsuranceLn 23 | $24K | $9K | $15K | |
| Other expenses (24a–d)Ln 24 | $147K | $141K | $4K | $2K |
| Total functional expensesLn 25 | $4.9M | $4.5M | $474K | $4K |
Filing history
| Year | Money in | Money out | In minus out | Net assets | Download |
|---|---|---|---|---|---|
| FY2025 Latest | $11.2M | $6.7M | $4.5M | $10.5M | 990 PDF |
| FY2024 | $6.7M | $5.9M | $768K | $6.0M | 990 PDF |
| FY2023 | $6.5M | $5.8M | $711K | $5.2M | 990 PDF |
| FY2022 | $6.4M | $5.9M | $492K | $4.5M | 990 PDF |
| FY2021 | $6.2M | $5.3M | $876K | $4.0M | 990 PDF |
| FY2020 Viewing | $5.3M | $4.9M | $375K | $3.1M | 990 PDF |
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Schedules filed Part IV
See the full FY2020 990 (6 parts)
Part I · Summary $5,307,911 revenue, 12 lines filed
Part VI · Governance 9 of 10 board members independent, no flags
Part VIII · Statement of revenue $5,307,911 across 8 lines filed
Part IX · Statement of functional expenses $4,932,486 across 14 lines filed
Part X · Balance sheet $7,842,960 assets, 14 lines filed
Part XI · Reconciliation of net assets $3,104,010 net assets at year end
Form 990 e-file (XML) FY2020 from the IRS · Classification, formation year and address from the IRS Business Master File
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