NIH Letters of Collaboration 2026: The New Format That Replaced Letters of Support
NIH has announced it's aligning its letter requirements with the format NSF has used for years, replacing "letters of support" with "letters of collaboration." The name shift matters less than what it signals about content. Here's what the new format expects and how to get your collaborators' letters right the first time.
Table of Contents
- Why NIH Changed the Format
- Letters of Support vs. Letters of Collaboration: What's Actually Different
- Who Needs to Provide a Letter and When
- What a Strong Letter of Collaboration Actually Contains
- How to Request Letters Without the Runaround
- Mistakes That Still Show Up Under the New Format
- Frequently Asked Questions
Why NIH Changed the Format
For years, researchers applying for both NIH and NSF funding faced two different systems for essentially the same document. NIH letters of support could run several paragraphs in any format the collaborator chose. NSF letters of collaboration were deliberately short, specific, and structured. The scientific community asked repeatedly why the two formats couldn't be harmonized, and investigators who applied to both agencies were maintaining two separate templates for what amounts to the same relationship commitment.
NIH's move toward alignment is part of a broader efficiency push that's included the SimplerNOFO initiative, the Forms-I application changes, and other streamlining moves over the past two years. The logic is sound: a shorter, more uniform letter is easier for reviewers to read, easier for collaborators to write, and harder to misuse as an informal reference letter or vague status endorsement. Whether that plays out uniformly across study sections and cycles will take a while to confirm, but the direction is clear.
What this means practically is that the meandering two-page letters from department chairs that once appeared in every R01 application should give way to something crisper. If your collaborators have ever written NSF letters, you can honestly tell them the ask is now similar.
Letters of Support vs. Letters of Collaboration: What's Actually Different
The old NIH letter of support could be almost anything. It could confirm that a department chair endorsed the applicant's research direction. It could come from a hospital affirming equipment access. It could come from a community partner confirming study site participation. The format was loose, the content varied widely, and reviewers often couldn't tell what, specifically, a letter was confirming. That ambiguity was the problem.
The new letter of collaboration is more constrained. It's intended to document a specific commitment: what the collaborating individual or organization will contribute, when, and on what terms. Think of it less as a character reference and more as a brief memo of understanding. A letter that says "I am happy to support Dr. X's research and believe this is important work" doesn't qualify under the new framing. A letter that says "I will provide access to our biobank of 5,000 samples for Aim 2, beginning in year two of the proposed project, at no cost to the grant" does.
The Core Distinction
A letter of support vouches for the applicant or the project's value. A letter of collaboration commits the writer to a specific role in carrying out the proposed work. The first is a testimonial. The second is a lightweight agreement. NIH now wants the second.
For applicants, the shift also means you can no longer treat letters as a low-cost way to display your network. A letter from a prominent investigator who isn't actually contributing anything to the proposed work doesn't help and may invite a question about why that person isn't on the budget.
Who Needs to Provide a Letter and When
Not every person acknowledged in your application needs a letter of collaboration. Letters should document contributions that are material to the proposed science, particularly contributions a reviewer might otherwise doubt are real or available.
The categories that typically warrant letters include external collaborators who will contribute data, samples, or expertise central to a specific aim; core facilities or specialized equipment at other institutions where access isn't guaranteed by institutional membership; community partners providing study participants or sites; and co-investigators at subaward institutions (though those relationships are also documented through the consortium agreement). Faculty collaborators at your own institution generally don't need a formal letter, but verify against your funding opportunity announcement, since some mechanisms require them.
Key personnel listed in your budget don't need a separate letter of collaboration. Their commitment is already documented through their effort on the application. Where things break down is when applicants name consultants or collaborators in the narrative who aren't on the budget, creating a question about whether those contributions are real or aspirational. If someone is doing meaningful work on your project, they should either be on the budget or have a letter explaining exactly what they're contributing and why it's outside the budget.
What a Strong Letter of Collaboration Actually Contains
A strong letter under the new format answers three questions: What specifically will the collaborator contribute? When does that contribution occur? Are there any conditions or costs attached?
Structure of a Solid Letter
- Opening line: Name the applicant and the grant title or mechanism. State the collaborator's role in one sentence.
- Specific contribution: One or two sentences naming the resource, expertise, or access being offered. Reference the specific aim or project phase where relevant.
- Terms: Any cost-sharing, timeline constraints, or conditions. If access is unconditional and at no cost, say so explicitly.
- Closing: Confirm the collaborator's awareness of the proposed workload and their capacity to fulfill this commitment during the project period.
Length isn't a virtue here. A well-structured letter of collaboration can be 150 to 200 words and still contain everything a reviewer needs. Letters longer than that are usually padded with introductory language about how important the science is, which is exactly the content the new format is designed to move away from.
One thing the letter should never be: a summary of your research aims written by someone who clearly didn't write it themselves. Reviewers notice when a collaborator's letter uses technical language that doesn't match anything else the collaborator has published. A generic letter drafted entirely by the PI and signed by the collaborator without edits tends to read that way, and it does more harm than a shorter, plainer statement the collaborator actually owns.
How to Request Letters Without the Runaround
Chasing collaborators for letters is one of the most time-consuming parts of grant preparation, and the format change doesn't fix that. But the new, shorter format gives you a real reason to frame the ask as lighter. You can honestly tell collaborators that NIH now prefers a brief, structured commitment statement rather than a full-length endorsement letter.
Draft the letter for them. This is standard practice and ethically appropriate. The draft should contain only verifiable facts about the collaboration: the resource they're committing, the timeline, any relevant terms. Don't use the draft to slip in endorsements of your scientific approach that they can't independently evaluate. When collaborators know exactly what they're being asked to confirm, the back-and-forth drops substantially. Include a short bullet list of the three specific things you need the letter to cover, and attach the draft.
Set your request deadline at least two weeks before your internal institutional deadline, not two weeks before the NIH receipt date. Institutional routing takes real time, and a collaborator at another university may need their own sponsored research office to review the letter. Clinical partners often need four weeks minimum. If a collaborator routinely fails to return documents before the deadline, consider whether their contribution is genuinely necessary or whether you can restructure the application to not rely on it.
Mistakes That Still Show Up Under the New Format
Letters that endorse rather than commit
"I strongly support Dr. X's research and believe it will advance the field" is an endorsement, not a collaboration statement. It gives the reviewer no useful information about what the writer will actually contribute. Under the new format, letters like this are a warning sign that the collaboration may be nominal rather than operational.
Letters for people already listed in the budget
Key personnel with effort on the application don't need a separate letter confirming participation. Including one wastes attachment space and dilutes the signal of the letters that actually matter. Only include letters for individuals whose role isn't already documented elsewhere in the application.
Vague resource commitments
"We can provide access to our imaging facility" isn't a commitment. "We will reserve 200 hours of instrument time at our standard internal rate, beginning in project year one" is. The specificity is what separates a meaningful letter from a placeholder that reviewers discount.
Missing letters for named-but-unbudgeted collaborators
If your Approach depends on access to a resource or expertise you don't own and can't demonstrate in your preliminary data, reviewers expect a letter confirming that access is real. A missing letter for a collaborator you named in the text is read as a feasibility gap, not an oversight.
Frequently Asked Questions
Does every NIH application require letters of collaboration?
No. Letters are required when your funding opportunity announcement specifies them, or when you have external collaborators contributing resources that are critical to the proposed work and not otherwise verifiable. Many single-PI R01s with only internal collaborators submit with no letters at all. Always check your NOFO instructions first; requirements vary by mechanism and institute.
Where do letters go in the application?
Letters are typically uploaded to an "Other Attachments" or dedicated letters attachment field in ASSIST, depending on the mechanism. Some FOAs specify a particular attachment slot. Follow your NOFO instructions exactly — attachment placement varies by forms version and mechanism. When in doubt, the NOFO and the application guide take precedence over general practice.
Can a collaborator at my own institution provide a letter?
Yes, though internal collaborators typically don't need formal letters if they're on the budget or if resource access is guaranteed by institutional policy. A letter from an internal core facility director committing specific instrument time is useful and appropriate. A general endorsement from a departmental colleague adds little and may look like letter-padding to reviewers who have seen the practice before.
How does this change affect resubmissions?
For A1 resubmissions, update any letters written under the old format. A letter from your original A0 that reads as a general endorsement should be replaced by a specific collaboration statement, both because the format has changed and because the collaboration itself may have evolved. Reviewers who see the same generic letter on a resubmission often read it as a signal that the relationship hasn't advanced since the first submission.
Build the Rest of Your Application on Solid Ground
Getting the letters right is one piece of a fundable application. Use these tools to understand the funding landscape in your research area before you finalize your aims and approach.
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