NIH allows one resubmission for most grant applications — the A1. Under the current review system, if the A1 does not score well enough to be funded, the applicant must submit a new application (an A0) rather than a second resubmission. This policy, which eliminated the A2 resubmission in 2009, means that investigators have one resubmission opportunity to demonstrate that the original application's concerns have been addressed. How that opportunity is used determines whether the application succeeds or whether the science must be repackaged entirely for a third submission cycle.
Analysis of NIH funding data shows that A1 resubmissions improve their scores relative to the original application in approximately 60 to 70 percent of cases, according to data reported in JAMA and analysis from NIH's own reporting systems. Applications that fail to improve — or that score worse on resubmission — almost always have the same underlying problem: the revision addressed the written text of reviewer concerns without addressing the underlying scientific or presentation problem that generated those concerns.
Reading Between the Lines of the Summary Statement
The NIH summary statement contains the written critiques of the primary reviewers plus a meeting summary that describes how the discussion unfolded and what the full panel concluded. This document is dense with information, but not all of it is at the surface. Understanding how to extract the full revision strategy from a summary statement requires distinguishing between three different types of concerns: those that reflect genuine scientific problems, those that reflect writing failures, and those that reflect reviewer priors or misunderstandings that the application failed to preempt.
Genuine scientific concerns — inadequate controls, insufficient sample size for the claimed power, a proposed method that cannot discriminate between competing hypotheses — require changes to the science. Writing failures — unclear Significance, underwritten Innovation, an Approach section that describes what will be done without explaining why those specific design choices were made — require changes to the presentation of science that may already be sound. Reviewer priors — assumptions about field standards or methodological expectations that the application did not address because the investigator did not anticipate them — require additions to the application that preempt those concerns before they arise.
Investigators who read every summary statement concern as a genuine scientific concern make too many changes to the science and not enough changes to the writing. Investigators who read every concern as a writing failure make too few changes to the scientific design. The skill is distinguishing between these categories — a task that requires reading the summary statement not just for what it says but for what it implies about what the reviewer needed that the application did not provide.
Signals in Reviewer Language
Reviewer language in summary statements contains reliable signals about whether a concern is a scientific problem or a communication problem. Understanding these signals reduces the risk of misdiagnosis.
"The significance is not convincingly established" almost always indicates a communication problem. Reviewers who understand the field and know the significance of a research area will use language like "the significance is not adequately articulated" rather than "the significance is not convincing" when the problem is the writing. When reviewers say significance is not "convincingly established," they often mean the application failed to translate the significance from expert language that the investigator finds obvious into accessible language that worked for the full panel.
"The proposed approach has not been validated" indicates either a genuine scientific problem (the method is novel and unproven) or a presentation problem (preliminary data exist that were not foregrounded appropriately). Checking whether the concern corresponds to existing but unpresented preliminary data helps distinguish these cases.
"The sample size appears insufficient" almost always requires a response that addresses the underlying concern — either a power analysis demonstrating adequacy of the proposed sample, a revised sample size with a corresponding budget adjustment, or a reframing of the aims to match what the current sample can support. This is a genuine scientific concern that cannot be addressed through presentation changes alone.
The diagnostic question: For each reviewer concern, ask: "If I called this reviewer and explained the background they are missing, would the concern disappear?" If yes, the concern is a communication problem — the fix is writing changes that provide that background explicitly. If no — if the concern would persist even with full information — it is a scientific problem that requires changes to the research design.
The Introduction Page: Building Confidence, Not Defending the Original
NIH's A1 resubmission includes a one-page Introduction that is read before the Specific Aims by reviewers assigned to the resubmission. This page has one purpose: to demonstrate to reviewers that the concerns from the previous cycle were taken seriously, understood accurately, and addressed substantively. It is not a cover letter, not a summary of changes, and emphatically not a defense of the original application against reviewer criticisms.
The most destructive pattern in A1 Introduction pages is the use of hedging language around reviewer concerns — responses that acknowledge a concern while implying it was not entirely legitimate. Phrases like "while the reviewers suggested X, we note that..." or "in response to concerns about Y, we clarify that our original approach was Z" signal defensiveness. Reviewers who encounter this language tend to re-read the resubmission looking for evidence that the underlying concern was not actually resolved — which is exactly what an Introduction page should be preventing.
An Introduction page that builds confidence follows a simple three-part structure for each significant concern: acknowledge the concern plainly ("Reviewers raised concerns about the adequacy of the sample size for Aim 2"), state specifically what was changed ("We have increased the sample size from N to N' and have added a power analysis demonstrating 80% power at the revised N for the primary outcome"), and direct readers to where the change appears ("Full power analysis is presented in the Approach section, p. 8"). This structure leaves no ambiguity about whether the concern was addressed or where to find the evidence.
When to Change the Science vs. When to Change the Framing
The most consequential resubmission decisions are about scope. Should the resubmission propose materially different science than the original application, or should it propose the same science with improved framing and additional supporting data? The answer depends on the nature of the concerns and the strength of the original scientific concept.
Applications whose core scientific concept was endorsed by reviewers but whose specific design, aims, or preliminary data were criticized are almost always best served by changing the framing and evidence rather than the concept. Changing the science in response to a writing-level concern signals that the investigator did not understand the original concern — or that they lacked confidence in the original concept — neither of which inspires confidence on resubmission.
Applications whose original scientific concept was questioned — where reviewers raised concerns about whether the question was scientifically sound, whether the proposed mechanism was plausible, or whether the approach could generate useful knowledge — require genuine scientific rethinking. A resubmission that reorganizes the original application around a concept that reviewers doubted is unlikely to succeed regardless of how skillfully the Introduction page is written.
NIMH guidance on resubmissions is explicit: "Applicants should carefully review the summary statement and plan their revision to directly address reviewer concerns." The word "directly" is doing work in that sentence. A revision that responds to every written concern without identifying and resolving the underlying issue that generated those concerns has not responded directly — it has responded literally, which is not the same thing.
Presenting New Data in a Resubmission
Resubmissions that include new data generated between the original application and the A1 have a structural advantage: they can demonstrate that the research is progressing and that the concerns about feasibility or approach are already being resolved by ongoing work. NIH guidance permits and encourages the inclusion of new preliminary data in resubmissions, and study section reviewers who see relevant new data in an A1 typically interpret it as evidence of the investigator's productivity and the research program's momentum.
The strategic challenge is positioning new data correctly. New data should be presented specifically in relation to the reviewer concerns that prompted it. Preliminary data that was generated to address a specific concern about feasibility should be introduced in the context of that concern — in the Approach section where the concern was originally raised, not just in a preliminary data section at the front of the Research Strategy where its connection to the specific concern may not be obvious.
New data placement: For every piece of new preliminary data in a resubmission, identify the specific reviewer concern it addresses. Place the data in the section of the Research Strategy most directly associated with that concern, and add a cross-reference to it in the Introduction page. Reviewers who encounter new data in the middle of the Approach section need to understand immediately why it is there and which concern it resolves — context that does not appear automatically from the data itself.
The A1 That Argues vs. The One That Resolves
The difference between an A1 resubmission that improves its score and one that does not is almost always a difference between arguing and resolving. The A1 that argues provides additional justification for why the original approach was correct. The A1 that resolves demonstrates that the specific concern no longer applies to the revised application.
This distinction appears in every part of the resubmission but is most visible in the Introduction page and in the revised sections that correspond to each reviewer concern. "We disagree with the reviewer's assessment that our sample size is inadequate because power analysis at the time of submission was based on X assumption" is an argument. "We have revised the sample size to N based on updated effect size estimates from [new pilot data] and have added a formal power analysis showing 80% power for the primary outcome at this N, presented on p. 8" is a resolution.
The argument may be scientifically correct. The resolution is what reviewers act on. Study sections discussing A1 applications are asking whether the concerns from the previous cycle have been resolved — and an application that makes arguments rather than resolutions leaves that question unanswered, regardless of the quality of the arguments.
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