An NSF Letter of Intent (LOI) is a short, non-binding, electronically submitted notice that a research team plans to submit a full proposal in response to a specific NSF program solicitation. It is required only when a solicitation says so — there is no blanket NSF-wide LOI requirement — and its purpose is entirely internal to NSF: helping program officers estimate how many proposals to expect and recruit enough qualified reviewers before the full-proposal deadline arrives.
This is a genuinely different document from an NSF Letter of Collaboration, which is a letter from an unfunded, uncompensated collaborator attesting to their role, submitted as part of the proposal package itself. The LOI is submitted by the proposing team to NSF, before the proposal exists in final form; the Letter of Collaboration is submitted with the proposal, by someone who isn’t part of the funded budget. Confusing the two — or assuming a solicitation that requires one also requires the other — is a real, avoidable compliance risk.
When NSF requires a Letter of Intent
Per NSF’s Proposal & Award Policies & Procedures Guide (PAPPG), the LOI requirement is set at the individual-solicitation level, not by the PAPPG’s general provisions. Chapter I of the PAPPG states plainly that the requirement to submit an LOI will be identified in the specific program solicitation a team is responding to — there is no standing rule that applies across NSF as a whole. Practically, this means:
- Check the solicitation text itself (and any associated Dear Colleague Letter) for an explicit LOI requirement and deadline — never assume based on a prior year’s competition or a similar program at another directorate, since requirements can change between competition cycles.
- Solicitations tend to request LOIs when NSF expects a large or hard-to-predict volume of proposals, when the review panel needs lead time to recruit reviewers with unusual subject-matter expertise, or when the competition involves large, multi-institutional, or center-scale awards where advance planning materially helps program management.
- Core disciplinary programs that run standing, predictable competitions are less likely to require an LOI than one-time or newly launched solicitations, though this is a pattern, not a rule — the solicitation is the only authoritative source.
What happens if a required LOI is skipped
This is the detail that makes the requirement worth taking seriously even though the LOI itself carries no scientific evaluation: per the PAPPG, if a solicitation requires an LOI and a team doesn’t submit one, NSF will not accept the resulting full proposal, or will return it without review. The LOI is a gate, not a formality — missing it can cost a team an entire submission cycle regardless of how strong the eventual full proposal would have been.
What an NSF Letter of Intent must include
Content requirements are set by the solicitation, but the PAPPG describes the standard elements NSF expects an LOI to contain:
- Principal Investigator name(s) — and co-PIs, where applicable.
- Proposed project title, matching (or closely previewing) the title the eventual full proposal will use.
- List of participating organizations, where the project involves more than one institution.
- A short synopsis of the proposed work — typically about one page — written with enough substantive detail that NSF program staff can identify the right subject-matter reviewers for the eventual panel. This is the part teams most often under-write: a vague synopsis does the one job an LOI actually has (reviewer/workload planning) poorly, even though the document isn’t scored.
For a proposal that will be submitted collaboratively across multiple organizations, NSF requires a single LOI covering the entire project, not one per participating institution — the PAPPG treats a collaborative proposal as one unified research project for this purpose, consistent with how NSF treats collaborative proposals generally.
How and when it’s submitted
LOIs are submitted electronically to NSF, following the specific instructions in the solicitation. Unless a solicitation directs otherwise, NSF’s standard proposal-related submission systems are Research.gov, Grants.gov, or the Broad Agency Announcement Management (BAAM) system — the solicitation will specify which one applies to the LOI itself, since it is not always the same system used for the eventual full proposal. The solicitation also sets the LOI’s own deadline, which falls a set period before the full-proposal deadline — the gap varies by competition and is stated explicitly in the solicitation; it is not a fixed PAPPG-wide number of days, so don’t reuse a deadline gap from a different program.
Letter of Intent vs. full proposal
An LOI is not a scaled-down proposal and is not evaluated the way one is:
- It is not externally reviewed and not used to make a funding decision — unlike the full proposal, no panel scores it.
- It is not binding. Submitting an LOI doesn’t obligate a team to submit the full proposal, and (outside of solicitation-specific restrictions) submitting a full proposal without a required LOI is the failure mode described above, not the reverse.
- It carries none of the required proposal sections (Project Description, Budget, Data Management Plan, Facilities, Biographical Sketches, etc.) — those apply only to the full proposal.
Letter of Intent vs. preliminary proposal
NSF also uses two-stage competitions in some programs, where a preliminary proposal is required before an invited full proposal. This is a materially different mechanism from an LOI: a preliminary proposal is substantive enough to be reviewed and used to decide whether a team is invited (or, in some programs, required) to submit a full proposal, and its purpose includes reducing wasted effort on proposals unlikely to be competitive and improving the eventual full-proposal quality. An LOI does none of that — it is purely an advance headcount-and-reviewer-planning notice, with no bearing on whether NSF will accept the subsequent full proposal (assuming it was submitted, since skipping a required LOI does have that consequence). Don’t assume a program’s ‘letter’ step is an LOI without checking whether the solicitation actually describes a preliminary proposal instead — the two have very different stakes.
How this compares to NIH’s letter of intent
Research administrators who also work with NIH should note the mechanisms have diverged. NIH operated a broadly similar, non-binding, roughly one-page LOI process for many years, requested by some funding opportunity announcements as a courtesy notice ahead of the application due date. That process was discontinued NIH-wide under NIH’s administrative-burden-reduction effort: NIH no longer requests or accepts Letters of Intent as part of the standard application process, and any LOI submitted to NIH will not be acknowledged or reviewed. See the CASRAI Dictionary’s Letter of Intent (NIH) entry for that history. NSF’s LOI mechanism has not followed suit — it remains a live, solicitation-specific requirement, and teams working across both agencies should not assume the two processes are converging or that either agency’s current practice predicts the other’s.
Frequently asked questions
Does every NSF program require a Letter of Intent?
No. There is no NSF-wide LOI requirement. Each solicitation states whether one is required; most standing, core disciplinary competitions do not require one, while some large, newly launched, multi-institutional, or center-scale competitions do.
Is an NSF Letter of Intent the same as a Letter of Collaboration?
No. An LOI is submitted by the proposing team to NSF before the full proposal, purely for internal planning purposes. A Letter of Collaboration documents an unfunded collaborator’s role and is submitted as part of the proposal package itself, under the PAPPG’s strict content restrictions for that specific document type.
Can NSF reject a full proposal for not submitting a required LOI?
Yes. Per the PAPPG, failure to submit a required LOI results in the full proposal either not being accepted or being returned without review.
Does submitting an NSF Letter of Intent commit a team to submitting the full proposal?
No. The LOI is non-binding and is not used to make a funding decision; it is a planning notice only.
Where do I find out if my target NSF solicitation requires a Letter of Intent?
In the solicitation itself — check the pre-submission or proposal-preparation section, and any related Dear Colleague Letter, rather than relying on a prior competition cycle’s requirements.
For the surrounding proposal-preparation workflow, see the grants management pillar, the guide to NSF collaborative proposal guidelines, and the dictionary entry for the NSF PAPPG itself.
