Letters of collaboration and letters of support are separate documents that may be either permitted or required attachments to a proposal submission. Details on the differences are identified in the Proposal and Award Policy & Procedures Guide (PAPPG). Anyone submitting a proposal should carefully read the PAPPG. Below, you’ll find answers to commonly asked questions on this topic, along with links to relevant portions of the PAPPG.

What is a Letter of Collaboration?
A letter of collaboration documents a collaboration between a principle investigator (PI) and other entities whose contributions are significant to a proposal. There are two types of collaborations:

• An unfunded collaboration is “any substantial collaboration with individuals not included in the budget.” These contributions must be documented in a letter of collaboration from each collaborator. Each letter should contain only the statement of collaboration described below – letters that include additional information will be omitted from the proposal. Unfunded collaborations should also be described in the Facilities, Equipment and Other Resources section of the proposal.
• A funded collaboration is one where a collaborative activity is identified in the proposal budget. Refer to Chapter II.D.3 in the PAPPG for instructions on how to complete the budget.

What is the recommended wording for a letter of collaboration?
“If the proposal submitted by Dr. [insert the full name of the Principal Investigator] entitled [insert the proposal title] is selected for funding by NSF, it is my intent to collaborate and/or commit resources as detailed in the Project Description or the Facilities, Equipment and Other Resources section of the proposal.”

What is a Letter of Support?
A letter of support is a requirement of specific programs or solicitations and is not a standard component of an NSF proposal. The letter aims to increase enthusiasm for the project or to highlight the qualifications of the PI or co-PI. Letters of support typically come from key stakeholders such as a department chair or mentor and must be unique to the specific proposal. Programs such as Transitions (NSF 20-505) and CAREER (NSF 20-525) require a letter of support from the department chair. Unless specified by the solicitation, a letter of support is generally 1-2 pages in length.

Letters of support should not be submitted unless required by the solicitation. An unsolicited letter of support may cause a proposal to be returned without review.

The following table highlights key differences and similarities between a letter of collaboration and a letter of support:

	Letter of Collaboration	Letter of Support
Optional or Required?	May be submitted with any proposal	May only be submitted if required by the program or solicitation
Impact on proposal processing?	Improper letters may be removed from the proposal; however, the proposal will still be accepted	Inclusion when not required may cause the proposal to be returned without review
Impact on proposal length?	Neither counts against the 15-page limit