Multi-PI Proposals: How to Structure Research Teams That Reviewers Find Credible

In July 2024, NIGMS published a blog post with a warning that most early-career investigators had never considered: if you are an early stage investigator and you join a multi-PI R01, you lose your ESI status the moment the award is made. You become ineligible for the ESI payline advantage, ineligible for MIRA, and statistically less likely to land the single-PI R01 that establishes your independent lab. The post was polite. The implication was stark -- for some junior faculty, saying yes to a multi-PI invitation is a career-limiting decision disguised as a collaboration opportunity.

That tension -- between the genuine scientific value of team science and the structural risks of doing it wrong -- runs through every multi-PI application. NIH introduced the multiple PD/PI model in 2007 specifically to support projects that could not be accomplished under the traditional single-investigator framework. Nearly two decades later, the mechanism is widely used but unevenly understood. Many applicants treat the leadership plan as an afterthought, bolt on a co-PI to shore up a weak biosketch, or skip the hard conversations about governance until a reviewer forces the issue.

This guide covers the structural, strategic, and bureaucratic dimensions of multi-PI proposals at NIH and NSF -- the parts that determine whether your team reads as credible or contrived.

When Multi-PI Strengthens an Application (and When It Does Not)

The threshold question is whether the science requires multiple leaders with genuinely distinct expertise, or whether you are adding names to compensate for a gap that could be addressed with a consultant, collaborator, or co-investigator.

Multi-PI applications are strongest when the project sits at the intersection of two or more disciplines and no single investigator possesses the training, equipment, or institutional access to execute all aims. A neuroscientist studying opioid receptor dynamics in clinical populations may need a co-PI who runs a substance use disorder clinic with an enrolled cohort. A computational biologist modeling protein-RNA interactions may need a co-PI with a wet lab capable of validating predictions experimentally. In these cases, the multi-PI structure is not a courtesy -- it reflects the actual intellectual architecture of the project.

Multi-PI applications weaken when the PIs have overlapping expertise, when one PI is clearly junior and lacks an independent role, or when the partnership exists primarily for strategic rather than scientific reasons. NIGMS has flagged several specific patterns that concern reviewers: PIs listed without identified functions, senior PIs in courtesy roles who contribute little beyond reputation, junior PIs elevated to PI status before they have the track record to lead, and expanded teams assembled primarily to justify additional salary support.

The acid test is whether removing any single PI would fundamentally change the project's feasibility. If the answer is no, that person should be a co-investigator or consultant, not a PI.

The Leadership Plan: What Reviewers Actually Evaluate

Every multi-PI application at NIH must include a Leadership Plan. Under the Simplified Peer Review Framework that took effect for applications submitted on or after January 25, 2025, the leadership plan is evaluated as part of Factor 3: Expertise and Resources. Reviewers assess whether the investigators have "complementary and integrated expertise" and whether the leadership approach, governance, and organizational structure are appropriate for the project.

Factor 3 is scored as a binary -- "appropriate" or "additional expertise/resources needed" -- with narrative comments required only when gaps are identified. This means a weak leadership plan will not directly tank your numerical score the way a flawed approach section will. But it will generate reviewer comments that erode confidence in the overall application, and those comments influence the discussion that shapes the final impact score.

NIAID's guidance on strong leadership plans identifies several elements that distinguish adequate plans from compelling ones.

Rationale. The plan must explain why the multi-PI model is necessary for this project. Generic statements about the value of collaboration do not satisfy this requirement. The rationale should reference specific aims and explain which PI leads which components, and why each PI's expertise is essential rather than merely helpful.

Governance structure. Describe how decisions about scientific direction are made. Who has final authority on experimental priorities, personnel decisions, and publication strategy? If the PIs have equal authority, how do they resolve disagreements? If one PI has seniority, how is the junior PI's intellectual contribution protected?

Communication plan. Reviewers expect specifics: weekly lab meetings, monthly PI-to-PI calls, quarterly progress reviews, annual retreats. The frequency matters less than the evidence that you have thought about how geographically or institutionally separated teams stay aligned.

Conflict resolution. This is the section most applicants underwrite. NIH explicitly recommends including an external mediator -- a department chair, a center director, or another respected scientist outside the project -- who can arbitrate disputes the PIs cannot resolve bilaterally. Naming this person in the plan signals that you have anticipated friction and built a mechanism to handle it before it derails the science.

Contingency planning. What happens if one PI changes institutions, takes a leave of absence, or leaves the project? The best plans address these scenarios directly, including whether the remaining PI can assume temporary oversight of the departing PI's aims and how budgets would be redistributed.

Role Differentiation: The Architecture That Matters Most

The single most common structural flaw in multi-PI proposals is insufficient differentiation between the PIs. When two investigators appear to do roughly the same thing, reviewers question why the project needs two leaders instead of one.

Effective role differentiation operates on at least three dimensions.

Scientific expertise. Each PI should bring a domain of knowledge the other does not possess. This is table stakes. But many applications stop here, listing complementary expertise without explaining how that expertise maps onto the actual work plan.

Methodological capacity. Beyond what each PI knows, the plan should articulate what each PI can do that the other cannot. One PI may run a clinical trial site; the other may operate a genomics core. One may have expertise in qualitative community-based research; the other in geospatial analysis. These are not interchangeable contributions.

Aim ownership. Each PI should have clear ownership of at least one specific aim or major project component. Shared ownership of all aims is a red flag. It suggests either that the PIs have not divided the work or that the division is artificial. The strongest applications assign primary responsibility for each aim to one PI while identifying specific sub-tasks where the other PI contributes.

A practical structure that reviewers find credible: PI-A leads Aims 1 and 3 (basic science and computational modeling), PI-B leads Aims 2 and 4 (clinical recruitment and translational validation), and both PIs share oversight of the integration aim where their outputs converge. This is concrete, testable, and impossible to accomplish under a single-PI model.

Budget Allocation Across Institutions

When multi-PI applications span multiple institutions, the budget structure becomes both a logistical challenge and a signal to reviewers about the seriousness of the collaboration.

NIH multi-PI awards are made as a single grant to one institution (the prime), with subcontracts funding the components at other institutions. The standard consortium budget format applies, and the leadership plan should describe how resources are distributed across PIs.

Several budgeting principles matter for credibility.

Proportionality. The budget allocated to each PI should be roughly proportional to the scope of work they are responsible for. A PI listed as co-leading the project but receiving 8% of the budget will raise questions about whether their role is substantive. Conversely, a PI receiving 50% of the budget but responsible for only one of four aims invites scrutiny.

Effort commitments. Each PI's percent effort must be appropriate and justified. NIH does not require equal effort across PIs, but the effort levels need to reflect actual scientific leadership, not token participation. A PI committing 5% effort to a project is, in practical terms, contributing roughly two hours per week. Reviewers know this arithmetic.

Resource reallocation. The leadership plan should describe the process for reallocating funds between PIs during the project period. This typically requires joint agreement, and NIH may include terms in the Notice of Award reflecting the initial allocation. Building a mechanism for reallocation -- triggered by milestone completion or shifting research priorities -- demonstrates mature project management.

Indirect cost rates. Each institution applies its own federally negotiated indirect cost rate to its portion of the budget. This means the same amount of direct costs produces different total costs depending on where the work is performed. Budget justifications should be transparent about this, and PIs should discuss it early to avoid surprises that surface during institutional review.

NSF Collaborative Proposals: A Different Structural Model

NSF handles multi-investigator proposals differently from NIH, and the choice of submission format has downstream consequences for administration, reporting, and intellectual credit.

NSF offers two models for collaborative research across institutions.

Single proposal with subawards. One institution submits, receives the award, and issues subcontracts to collaborating institutions. The lead PI bears primary responsibility for reporting and communication with NSF. This model is simpler administratively but concentrates control at the lead institution.

Simultaneous submission of linked proposals. Each institution submits its own proposal through Research.gov, and NSF links them together. Each institution receives its own award. All proposals must use identical titles beginning with "Collaborative Research:" and must share the same start date, duration, and NSF program designation. This model distributes administrative responsibility and gives each PI direct accountability to NSF.

The linked-proposal model is generally preferred when collaborating institutions want budgetary independence and when each PI needs the award to appear on their own institutional record for tenure and promotion purposes. The subaward model is more practical when one institution is clearly leading and the collaborating institution's contribution is more narrowly defined.

Regardless of format, NSF collaborative proposals require a clear management plan that addresses coordination mechanisms, data sharing, and communication. The expectations are similar to NIH's leadership plan requirements, though the format is less prescriptive.

The ESI Trap: Career-Stage Implications of Multi-PI Awards

For early-career faculty at NIH-funded institutions, the decision to join a multi-PI application carries implications that extend well beyond the project itself.

Under current NIH policy, a multi-PI R01 application qualifies for ESI consideration only if every PI on the application holds ESI status. If even one PI is an established investigator, the application loses ESI eligibility entirely. This means the junior PI forfeits the ESI payline advantage -- which at some institutes can be 5 to 10 percentile points more favorable than the standard payline.

More consequentially, once an ESI receives any R01 award -- including a multi-PI R01 -- they lose ESI status permanently. They can no longer submit future applications as an ESI. At NIGMS specifically, a multi-PI R01 does not qualify as a prerequisite for the Maximizing Investigators' Research Award (MIRA), which means a PI whose only NIGMS R01 is a multi-PI award cannot transition to this major funding mechanism.

The strategic calculus depends on the junior PI's specific situation. An ESI who already has a strong single-PI R01 application under review may want to avoid a multi-PI commitment that could strip their ESI status before that application is scored. An ESI whose research genuinely requires a collaborative framework -- and who is unlikely to mount a competitive single-PI application in the near term -- may find the multi-PI path worth the tradeoff.

The key is that this should be a deliberate decision, not a default one. Junior faculty should consult their program officer and their department chair before agreeing to join a multi-PI application, and the leadership plan should explicitly address how the junior PI's independence and career development will be supported within the team structure.

Writing the Plan: Structural Checklist

Strong leadership plans share a consistent architecture. Use this as a framework, adjusting the specifics to match your project and agency.

Section 1: Rationale for Multi-PI approach. Two to three paragraphs explaining why this project requires multiple PIs, referencing specific aims and the expertise gap that no single investigator can fill. Avoid generic language about the value of interdisciplinary collaboration.

Section 2: Roles and responsibilities. A table or structured list mapping each PI to their specific aims, methodological contributions, and supervisory responsibilities. Include percent effort and institutional affiliation.

Section 3: Governance and decision-making. Description of the decision-making process for scientific direction, personnel, publications, and budget. Identify who has final authority and how disputes are escalated.

Section 4: Communication plan. Specific meeting cadences (weekly, monthly, quarterly) with format (in-person, videoconference, asynchronous). Include mechanisms for trainee integration across labs.

Section 5: Conflict resolution. Name the external mediator. Describe the escalation path: bilateral discussion first, then mediation, then institutional intervention if necessary.

Section 6: Contingency plan. Address PI departure, institutional change, and loss of key personnel. Describe interim leadership arrangements and budget redistribution procedures.

Section 7: Data sharing and publication policy. Authorship conventions, data access protocols, and intellectual property agreements. This section is particularly important for industry-academic partnerships and cross-institutional collaborations.

The entire plan typically runs one to two pages. Brevity is a virtue -- reviewers are evaluating whether you have thought through the operational realities of team science, not whether you can write at length about collaboration theory.

The Bottom Line

Multi-PI proposals succeed when the team structure emerges from the science and fails when the science is retrofitted to justify the team. Reviewers can tell the difference. They have seen hundreds of leadership plans, and they know which ones represent genuine intellectual partnerships and which ones are administrative conveniences.

Before you add a second PI to your application, answer three questions honestly: Does this project require two leaders, or would a co-investigator suffice? Can each PI articulate a role that the other cannot fill? And is the junior investigator on this team making a deliberate career decision, or are they drifting into a commitment they have not fully evaluated?

If you can answer all three with confidence, the multi-PI model may be exactly right for your project. Build the leadership plan with the same rigor you bring to your specific aims, and the team structure becomes an asset rather than a liability.

Tools like Granted can help you identify funding opportunities where multi-PI applications are explicitly encouraged and match your team's combined expertise to the right programs.