Methodology & source manifest
Everything on the National Science Foundation monitor derives from public records — the NSF FY2027 Budget Request to Congress, OMB Historical Tables, the USAspending API, and reachable NSF OIG / NSF Agency Financial Report / GAO oversight documents. This page is the audit trail: method, sources, validation, and every flag.
Method
Discretionary research vs. the mandatory ARV
NSF is almost entirely discretionary research funding — the appropriated research, facilities, and operations that make up the headline. The FY2027 request also adds $900.0M of new mandatory authority for construction of the Antarctic Research Vessel (ARV). That is the single reason the mandatory total jumps, and it is kept strictly separate: mandatory funding is never folded into the discretionary research headline. Blending the ARV into the discretionary ask would overstate NSF's appropriated research base and misread a one-time construction line as program funding — the cardinal error in the NSF budget.
A directorate-split data limit
The dominant Research & Related Activities account is broken out by directorate — but the NSF Summary Table publishes that by-directorate detail only for the FY2025 Current Plan and the FY2027Request. There is no published FY2026 directorate split, so the FY2026 column is omitted in the directorate view — disclosed and left blank, never fabricated. Within the FY2027 request, SBE is proposed for elimination ($0) and EDU is consolidated into R&RA; both are shown exactly as the source states.
Source documents & validation ledger
The history layer is shown in nominal dollars only — OMB Historical Table 5.2 publishes no constant-dollar basis, and no deflator is synthesized. It is agency-wide budget authority, which includes the one-time FY2009 ARRA appropriation and the post-CHIPS ramp; neither is conflated with the annual discretionary base, and the mandatory Antarctic Research Vessel is never folded into the discretionary research headline.