Updated: March 27, 2026
NIH Funding Glossary
A comprehensive reference of key NIH grant terminology. Whether you are writing your first F31 or managing an R01 portfolio, this glossary covers activity codes, review processes, funding mechanisms, and research administration terms every researcher should know.
A
Activity Code
A six-character code that identifies a specific category of NIH extramural funding. Activity codes describe the type of research support, such as R01 for research project grants, K08 for mentored clinical scientist awards, or T32 for institutional training grants. Understanding the right activity code is essential when choosing which grant mechanism to apply for.
Administrative Supplement
Additional funding added to an existing active grant to cover costs not anticipated in the original application. Administrative supplements do not require peer review but must be approved by the funding Institute or Center. They are commonly used to support diversity initiatives, add new research directions, or address unexpected costs.
Application Receipt Date
The deadline by which a grant application must be submitted to NIH. Standard receipt dates occur three times per year for most activity codes (typically in February, June, and October). Some Funding Opportunity Announcements specify different receipt dates. Missing the deadline means waiting for the next cycle.
Award Notice Date
The date on which the NIH officially issues a Notice of Award (NOA) for an approved and funded grant. This is the formal notification that funds have been obligated and the project can begin. The award notice date typically falls after council review and successful Just-in-Time negotiations.
B
Biosketch
A standardized document (up to five pages) summarizing an investigator's qualifications, positions, publications, and contributions relevant to the proposed research. NIH requires the use of a specific biosketch format that emphasizes the significance of up to five key contributions rather than a simple publication list. An effective biosketch demonstrates the investigator's expertise and productivity.
Budget Justification
A written narrative explaining why each cost listed in a grant budget is necessary for the proposed research. Reviewers evaluate whether the requested resources are appropriate and reasonable. A strong budget justification links every line item directly to the specific aims and experimental plan.
Budget Period
The interval of time (usually 12 months) into which a project period is divided for budgetary and funding purposes. NIH awards funds one budget period at a time, and continued funding depends on scientific progress, available funds, and compliance with grant terms. Most R01 grants have five budget periods within their total project period.
C
Center Grant (P-series)
A category of NIH grants that support multi-project, interdisciplinary research programs. P30 grants fund core facilities that serve a broad research community, while P50 and P01 grants support coordinated research projects around a central theme. Center grants typically require strong institutional commitment and an established track record of collaboration.
Clinical Trial
A research study in which human participants are prospectively assigned to one or more interventions to evaluate the effects on health-related outcomes. NIH has specific requirements for clinical trial applications, including registration on ClinicalTrials.gov, Good Clinical Practice training, and a data safety monitoring plan. Since 2018, NIH uses a single definition of clinical trial across all institutes.
Co-Investigator (Co-I)
A researcher who contributes to the scientific development or execution of a project but does not direct it. Co-investigators share responsibility for specific aspects of the research and contribute to the biosketch and other support sections. Unlike a Multiple PI arrangement, co-investigators do not carry equal leadership authority for the grant.
Competing Renewal
An application to extend funding for an existing grant beyond its current project period. Also called a Type 2 application, it undergoes full peer review and competes against all other applications. A strong renewal application demonstrates significant progress during the prior funding period and proposes a compelling new direction or continuation.
Council Review
The second level of review in the NIH dual-review system. After peer review by a study section, applications are evaluated by the National Advisory Council or Board of the relevant Institute or Center. Council members consider the scientific merit score, relevance to the institute's mission, and portfolio balance. Council meets three times per year (January, May, September).
CSR (Center for Scientific Review)
The NIH organization responsible for receiving and assigning grant applications and organizing the initial peer review (study sections). CSR handles about 70% of all NIH applications. The CSR assigns each application to the appropriate study section based on its scientific content and to the appropriate Institute or Center based on its mission relevance.
D
Direct Costs
Expenses that can be specifically attributed to carrying out the proposed research, including personnel salaries, equipment, supplies, travel, and consultant costs. Direct costs are distinct from indirect costs (facilities and administrative costs), which cover institutional overhead. NIH caps salary charges at a congressionally mandated level, updated annually.
Diversity Supplement
An administrative supplement that provides funding to support individuals from underrepresented groups in biomedical research. These supplements are added to active parent grants and can support students, postdocs, or early-career investigators. The goal is to increase the diversity of the research workforce by providing protected research time and mentoring.
E
Early Stage Investigator (ESI)
A PI who has completed their terminal research degree or medical residency within the past 10 years and has not previously received a substantial, competing NIH research grant (such as an R01). ESIs benefit from special pay line considerations at most NIH institutes, which typically fund ESI applications at a higher percentile than established investigators. The ESI window can be extended for certain life events.
eRA Commons
The NIH's electronic research administration portal where investigators, institutional officials, and reviewers manage grant-related activities. Through eRA Commons, applicants can check application status, view summary statements, manage biosketches, and complete Just-in-Time requirements. Every PI must have an eRA Commons account before an application can be submitted.
Expedited Review
An accelerated review process sometimes used for applications that address urgent public health needs, such as emerging infectious disease outbreaks. NIH can convene special review panels outside the normal review cycle to evaluate time-sensitive applications. This mechanism was used extensively during the COVID-19 pandemic.
F
F31 / F32 Fellowship
Individual predoctoral (F31) and postdoctoral (F32) fellowship awards that provide stipend support for research training. F31 awards support graduate students, while F32 awards support postdoctoral researchers. These fellowships require a detailed training plan, a strong mentoring environment, and an institutional commitment to the trainee's career development.
FOA (Funding Opportunity Announcement)
A formal notice published in the NIH Guide for Grants and Contracts that invites grant applications for a specific research area or mechanism. FOAs include Program Announcements (PAs), Requests for Applications (RFAs), and Notices of Special Interest (NOSIs). Each FOA describes the scope, eligibility, budget, and receipt dates for the opportunity.
Fiscal Year (FY)
The federal government's accounting year, which runs from October 1 through September 30. NIH grants and budgets are tracked by fiscal year. For example, FY2026 runs from October 1, 2025 through September 30, 2026. The fiscal year affects when funds are appropriated, awarded, and reported.
G
Grants.gov
The federal government's centralized portal for finding and applying to all federal grant opportunities, including NIH grants. Applicants must register their organization on Grants.gov before submitting an NIH application. The site publishes all NIH Funding Opportunity Announcements and provides the electronic submission pathway for applications.
Grant Number Format
NIH grant numbers follow a standardized format that encodes the activity code, institute, serial number, and other information. For example, 5R01GM123456-03 indicates a Type 5 (non-competing continuation) R01 grant from NIGMS, serial number 123456, in its third year. Understanding this format helps researchers look up specific grants in NIH RePORTER.
H
Human Subjects Research
Research involving living individuals about whom an investigator obtains data through intervention or interaction, or identifiable private information. NIH has specific requirements for human subjects protections, including Institutional Review Board (IRB) approval, informed consent, and data safety monitoring. Applications involving human subjects must address these protections in detail.
I
Indirect Costs (F&A)
Facilities and Administrative costs that represent an institution's overhead expenses related to supporting sponsored research. These include building maintenance, utilities, libraries, and administrative services. Each institution negotiates an indirect cost rate with the federal government. Indirect costs are added on top of direct costs and can significantly increase the total grant budget.
Institute / Center (IC)
One of the 27 Institutes and Centers that comprise NIH, each focused on specific diseases or research areas. Examples include NIGMS (basic biomedical research), NCI (cancer), and NIMH (mental health). Each IC sets its own research priorities and pay lines. Choosing the right IC for your application is critical for funding success.
Investigator-Initiated Research
Research projects proposed by scientists based on their own ideas, as opposed to research solicited by NIH through targeted FOAs. The R01 is the primary mechanism for investigator-initiated research and represents the largest share of NIH's extramural portfolio. Investigator-initiated grants are submitted in response to parent announcements that accept applications on any health-related topic.
IRG (Integrated Review Group)
A cluster of study sections organized around a broad scientific area within the Center for Scientific Review. For example, the Immunology IRG contains multiple study sections covering different aspects of immune function. Understanding which IRG and study section will review your application can help you frame your specific aims and significance effectively.
J
Just-in-Time (JIT)
A process by which NIH requests certain administrative information only after an application has been reviewed and scored favorably. JIT materials typically include updated Other Support documents, IRB approval letters, verification of ESI status, and any other pending items. Receiving a JIT request is a positive sign that your application may be funded, but it is not a guarantee.
K
K-series Awards (K01, K08, K23, K99/R00)
Career development awards that provide salary and research support for early-career investigators transitioning to independence. K01 awards support mentored research scientists, K08 and K23 awards support mentored clinical investigators, and K99/R00 (Pathway to Independence) awards bridge the transition from postdoc to faculty. Each K mechanism has specific eligibility requirements and protected research time expectations.
L
Letter of Intent (LOI)
A brief notification to an NIH Institute or Center indicating that you plan to submit an application in response to a specific FOA. While usually optional, submitting an LOI helps NIH plan the review process and can facilitate communication with Program Officers. An LOI is typically a one-page document that summarizes the proposed research and key personnel.
M
Modular Budget
A simplified budget format used for applications requesting up to $250,000 in direct costs per year. Instead of detailed line items, the budget is requested in modules of $25,000 each. A brief narrative justifies personnel and any costs above $25,000. Most R01, R03, and R21 applications use the modular budget format.
Multiple PI (MPI)
A grant leadership structure in which two or more PIs share authority and responsibility for directing the research project. MPI applications must include a Leadership Plan describing how the PIs will coordinate their efforts and resolve disputes. This model is appropriate when a project requires true intellectual partnership across complementary areas of expertise.
N
New Investigator
A PI who has not previously received a substantial, competing NIH research grant as PI or MPI. The definition is broader than Early Stage Investigator because it does not include the 10-year time limit. Some NIH policies and special initiatives extend benefits to all new investigators, not only ESIs.
NIH Guide for Grants and Contracts
The official publication for NIH funding opportunities, policy notices, and programmatic announcements. Published weekly, the NIH Guide is the authoritative source for all FOAs, Notices of Special Interest, and policy changes. Researchers should monitor the Guide to stay current on opportunities relevant to their work.
NIH RePORTER
A publicly accessible database that allows users to search, browse, and analyze NIH-funded research projects. RePORTER contains information on grants, investigators, publications, patents, and clinical trials associated with NIH funding. It is the primary tool for exploring who is funded, for how much, and in what research areas.
Notice of Award (NOA)
The official, legally binding document notifying the grantee that NIH has approved and funded their application. The NOA specifies the amount awarded, the budget and project periods, terms and conditions, and reporting requirements. It is issued electronically through eRA Commons.
NOT (Notice)
A type of publication in the NIH Guide that communicates important information such as policy changes, clarifications, reminders, and Notices of Special Interest (NOSIs). NOT numbers follow the format NOT-XX-YY-NNN, where XX identifies the issuing IC. Researchers should pay close attention to NOSIs, which signal priority areas that may receive preferential funding.
O
Other Support
A comprehensive document listing all sources of research support available to key personnel on a grant application, including active grants, pending applications, and in-kind contributions. NIH has significantly strengthened Other Support disclosure requirements in recent years, including the reporting of foreign government-sponsored talent recruitment programs. Accurate and complete reporting is a compliance requirement.
P
PA (Program Announcement)
A type of FOA that describes areas of increased scientific interest to one or more NIH ICs. PAs use the standard receipt dates and existing review mechanisms. Unlike RFAs, PAs do not set aside specific funds. The parent R01 announcement is a PA that accepts investigator-initiated applications on any health-related topic.
PAR (Program Announcement with Special Review)
A Program Announcement that uses special review criteria or a dedicated review panel instead of the standard study section process. PARs may also have specific receipt dates different from the standard schedule. The special review criteria are described in the FOA and may emphasize factors unique to the research area.
Pay Line
The percentile rank or priority score below which an NIH Institute or Center will generally fund applications. Pay lines vary by IC, fiscal year, and sometimes activity code. For example, an IC might set its R01 pay line at the 20th percentile, meaning applications scored in the top 20% of their study section are likely to be funded. Pay lines are not publicly guaranteed but are often shared informally by Program Officers.
Peer Review
The first level of the NIH dual-review system in which scientific experts evaluate grant applications based on specific review criteria. Reviewers assign scores for significance, investigator qualifications, innovation, approach, and environment. The peer review process produces a priority score and a summary statement that describes the strengths and weaknesses of each application.
Percentile
A ranking that indicates the relative position of an application's priority score among all scored applications reviewed by a particular study section at its last three meetings. A lower percentile is better; for example, a 10th percentile score means the application scored better than 90% of recent applications in that study section. Percentiles are the primary basis for funding decisions at most ICs.
Program Officer (PO)
An NIH scientist who manages a portfolio of grants within a specific research area at an Institute or Center. Program Officers can provide guidance on whether a research idea fits an IC's priorities, suggest appropriate funding mechanisms, and offer feedback on draft specific aims. Contacting a PO before submission is strongly encouraged and can significantly improve the fit of your application.
Project Period
The total length of time for which NIH approves support for a grant, typically three to five years for an R01. The project period is divided into budget periods (usually annual). At the end of the project period, a competing renewal application must be submitted to continue funding.
R
R01 (Research Project Grant)
The original and most common NIH grant mechanism, supporting a discrete, specified research project. R01 grants typically provide three to five years of funding with no explicit budget cap (though budgets over $500,000 in direct costs per year require special permission). The R01 is considered the gold standard for establishing an independent research program and is the benchmark for tenure and promotion at many institutions.
R03 (Small Grant)
A smaller NIH grant mechanism providing up to two years of funding at up to $50,000 in direct costs per year. R03 grants support pilot studies, secondary data analyses, feasibility studies, and other projects of limited scope. Not all ICs accept R03 applications, and some have phased out this mechanism in favor of R21s.
R21 (Exploratory/Developmental Grant)
A grant mechanism supporting exploratory or developmental research projects. R21 grants provide up to two years of funding at up to $275,000 in total direct costs. They are intended for high-risk, high-reward projects that may lack preliminary data. R21 applications do not include a preliminary data section, although reviewers often still look for evidence of feasibility.
R33 (Exploratory/Developmental Grant Phase II)
A grant mechanism that provides a second phase of support for projects that have demonstrated feasibility during an initial exploratory phase (often an R21). Some FOAs offer combined R21/R33 mechanisms where the R33 phase is contingent on achieving specific milestones during the R21 phase.
R35 (Outstanding Investigator Award)
A grant mechanism providing long-term, stable support to experienced investigators with outstanding track records. R35 awards from NIGMS (MIRA program) provide up to five years of funding and are intended to replace most of an investigator's other NIH support. The goal is to increase flexibility and reduce time spent on grant writing.
RFA (Request for Applications)
A type of FOA that solicits applications in a well-defined scientific area with set-aside funds. RFAs typically have a single receipt date and are reviewed by a specially convened panel rather than a standing study section. Because funds are dedicated, competition is limited to applications submitted to that specific RFA.
Resubmission (A1)
A revised application that addresses the critiques raised in the summary statement from the prior review. NIH allows one resubmission (designated A1) per application. The resubmission must include an Introduction page (one page for most mechanisms) that explains how the revised application responds to each major criticism. Resubmissions historically have higher success rates than initial submissions.
Review Criteria
The five scored criteria used by NIH peer reviewers to evaluate most research grant applications: Significance, Investigator(s), Innovation, Approach, and Environment. Each criterion is scored on a 1-to-9 scale, and the individual criterion scores inform the overall impact score. Additional review criteria (such as protections for human subjects) are evaluated but not scored separately.
S
Scientific Review Officer (SRO)
The NIH official who organizes and manages the peer review of grant applications within a study section. The SRO selects reviewers, assigns applications, leads the review meeting, and prepares the summary statement. SROs are the primary point of contact for questions about the review process and can provide information about how your application was discussed.
Specific Aims
A one-page document that serves as the cornerstone of an NIH grant application. The Specific Aims page states the overall objective, the central hypothesis, and the two to three specific aims that will test the hypothesis. Most reviewers consider this the most important page of the application, as it frames the significance, innovation, and approach of the entire project.
Study Section
A panel of external scientific experts convened by NIH (usually through CSR) to evaluate grant applications through peer review. Each study section has a defined scientific scope and typically reviews applications three times per year. Standing study sections have a stable roster of members who serve for four-year terms, while Special Emphasis Panels are assembled for specific review needs.
Subproject
An individual research project within a multi-component grant, such as a P01 or U54. Each subproject has its own specific aims, budget, and investigators, but is intellectually integrated with the other subprojects and the overall program. Subprojects undergo review as part of the parent application.
Success Rate
The percentage of reviewed applications that receive funding in a given fiscal year. NIH publishes success rates by activity code and IC. For R01-equivalent grants, the overall success rate has historically ranged from 20% to 25%, though it varies considerably by institute and year. Success rates are calculated differently from pay lines and provide a broader view of funding competitiveness.
T
T32 Training Grant
An institutional training grant that provides support for predoctoral and/or postdoctoral trainees in a specific research area. T32 grants are awarded to institutions, not individuals, and fund multiple training slots. They require a structured training program with a track record of producing successful scientists. T32 support includes stipends, tuition, and training-related expenses.
Type 1 Application (New)
An application for a grant that has not been previously funded. This is the standard initial application type. Type 1 applications are designated by the numeral "1" at the beginning of the grant number (e.g., 1R01GM123456-01).
Type 2 Application (Competing Renewal)
An application to extend a previously funded grant for an additional project period. Type 2 applications undergo full peer review and must demonstrate progress and propose new directions. The grant number begins with "2" (e.g., 2R01GM123456-06).
Type 3 Application (Supplement)
A request for additional funds to an existing grant, either as an administrative supplement or a competitive revision. Type 3 supplements can address expanded scope, new collaborations, or programmatic priorities such as diversity supplements.
Type 4 Application (Extension)
A request to extend the project period of a grant without additional funds. Type 4 extensions (no-cost extensions) allow investigators to use remaining funds beyond the original end date. The first no-cost extension of up to 12 months can be approved by the grantee institution; subsequent extensions require NIH approval.
Type 5 Application (Non-Competing Continuation)
The annual progress report and funding request for a multi-year grant that has already been approved through peer review. Type 5 awards do not require competitive review but are contingent on satisfactory progress and available funds. The grant number begins with "5" (e.g., 5R01GM123456-03).
U
U01 Cooperative Agreement
A funding mechanism similar to a grant but with substantial NIH scientific or programmatic involvement. In a U01, the NIH Program Officer plays an active role in the research through a steering committee or other collaborative structure. Cooperative agreements are used when a project benefits from close interaction between the investigator and NIH staff.
Unfunded Application
An application that was reviewed but did not receive a fundable score or was not selected for funding after council review. Applicants receive a summary statement with reviewer critiques, which should be used to strengthen any resubmission. An unfunded application with a good score may still be funded if additional money becomes available or through selective pay mechanisms.
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