Even researchers who back NIH's grant cap are warning it could backfire

A working lab at a major research university might run like this: a principal investigator holds three R01 grants at once, each typically worth a few hundred thousand dollars a year in direct costs, plus a smaller R21 for a high-risk pilot and an R03 for a focused question. The same investigator might also share a multi-PI P01 with collaborators, where a single award can total several million dollars over its lifetime. If NIH caps simultaneous grants by count, the first PI gets clipped; the second does not.

That asymmetry surfaced across the 3,307 comments NIH published in August, after a June Request for Information on capping simultaneous Research Project Grants per PI. NIH proposed a straight count cap. Commenters, including many who said they support the goal of spreading funding more widely, proposed a different unit: dollars, partial counting for multi-PI awards, or a minimum-effort threshold per grant.

Among the 3,307 usable comments NIH tallied, 40% opposed the count cap, 27% supported it, and 32% were mixed. The numbers do not show a clear winner. Within the mixed group, 44% preferred a cap of four simultaneous grants rather than three or two. Among supporters, 40% picked a cap of three. Among opponents, half said the agency should not cap simultaneous grants at all.

NIH is making the case under its Unified Funding Strategy, rolled out operationally in January: studies of diminishing marginal returns on individual grant funding, and findings that larger and more complex teams tend to produce less innovative work per dollar. NIH frames the cap as advancing "stewardship, workforce sustainability, and the goals of the NIH Unified Funding Strategy." The Leveraging Funding Policies Framework lays out the principles (scientific merit, breadth, career stage, geographic distribution, and institute-specific fund availability) that any new cap would have to fit.

Researchers who said they agree with the goal told the agency a count cap is the wrong instrument. The top alternative proposals in the comment file were not "no cap" but a redesign: a dollar cap (~750 responses), partial counting of multi-PI awards (~700), stricter enforcement of the existing scientific overlap rules (~700), exempting the small R03 and R21 mechanisms (~670), and a minimum PI effort per grant (~400). A total funding cap per lab drew about 250 responses. These are not fringe ideas. They are the redesign menu NIH is now choosing from.

The scale of the trade-off shows up in NIH's own impact table: a cap of four simultaneous RPGs would free roughly $1.28B and create about 1,900 new awards; a cap of three would free $2.04B and create 3,020; a cap of two would free $3.53B and create 5,230. Those are the funds the agency wants to redirect to early-career PIs and to institutes that currently fund a smaller share of their portfolio. They are also the funds that come out of established labs that, under the current system, hold multiple awards at once.

NIH's FY2025 baseline shows 10.7% of PIs held three or more simultaneous RPGs, 3.6% held four or more, and 1.2% held five or more. A cap at three would not touch the other 89% of PIs. A cap at two would reach deeper into the portfolio, though several of the largest dollar awards sit in multi-PI mechanisms the count cap does not reach.

Labs are already adjusting to the Unified Funding Strategy rollout, where individual institutes have moved away from uniform funding cutoffs toward their own funding plans. STAT+ reported that researchers who back the policy worry a straight count cap adds disruption in a period that is already tumultuous, and that the rule may be too simplistic a lever for the problem it is meant to solve.

NIH has not said which cap, if any, it will adopt, or whether it will move to a dollar cap, a hybrid, or a tightened overlap rule instead. The RFI comment file is public, and the agency has indicated that any change would land alongside, not after, the broader funding-strategy work already in motion.

If the goal is to spread funding more widely, the unit of the rule (count, dollar, or effort) decides who gets clipped and who walks through. NIH has the data. The redesign is on the table.