Research Note: Form 990 Data Quality and Reliability

Nonprofit financial transparency is vital for research, policy, and public trust. Yet IRS Form 990 data—the most widely used nonprofit data set—raises reliability concerns because it is unaudited and follows tax, rather than Generally Accepted Accounting Principles (GAAP) rules. We conduct two analyses to assess differences between Form 990 and audited financial statements. First, using 2015 to 2019 e-filings, we document the use of outside accountants, GAAP deviations, restatements, and obvious numerical errors. Second, we compare 574 New York 2018 Form 990s with their audits. Key balance sheet items align closely when both reports are prepared on a legal-entity basis, but agreement is lower for activity statements and ratios. Major discrepancies arise when financial statements are consolidated but the 990 is not, producing materially different program and fundraising ratios. We recommend verifying amended filings, addressing inconsistencies between consolidated and legal-entities, and reviewing part XI reconciliation items during data cleaning.