Request for Information: FDA-NIH Resource on Terminology for Clinical Research
Notice Number:

Key Dates

Release Date:

May 6, 2024

Response Date:
June 24, 2024

Related Announcements


Issued by

Food and Drug Administration (FDA) 



The purpose of this Request for Information (RFI) is to solicit public comments on the joint U.S. Food and Drug Administration (FDA) and National Institutes of Health (NIH) initiative to clarify clinical research terms related to innovative clinical study designs, including studies using real-world data (RWD) to generate real-world evidence (RWE).


FDA and NIH share a mutual interest in facilitating efficient, well-designed clinical research. Recent advances in science and technology, as well as innovative approaches to research design and methodology, have enhanced clinical research, such as by providing opportunities to increase efficiency in product development, facilitating use of RWE to support marketing authorizations, satisfying post-approval study requirements, and improving participant engagement in clinical trials.

For certain terms associated with clinical research, there appears to be a lack of consistency in how those terms are used across the clinical research ecosystem, especially around descriptions of innovative clinical trial designs and certain studies using RWD to generate RWE. In some cases, this lack of a consistent terminology results in diminished clarity where the same term may have different meanings to different parties. In other cases, inconsistent usage of terms has created specific challenges to understanding the intended meaning and impact of terms (e.g., pragmatic clinical trial, pragmatic elements, causal inference). These challenges may be particularly apparent when describing a study design in a protocol, communicating about planned research studies, or interpreting and describing research results. Thus, a shared understanding of the meaning of terms across the clinical research enterprise may facilitate efficiencies and effective communication.

To help address this challenge, FDA and NIH convened a working group to develop definitions for clinical research terms related to innovative clinical study designs, including studies using RWD to generate RWE, that support scientific, clinical, and/or regulatory decision-making. This work is intended to better facilitate communication within the clinical research community by helping to establish a common vocabulary to more uniformly characterize clinical research. In turn, the research community may be better situated to evaluate potential strengths and weaknesses of individual studies, and to clearly convey innovative aspects of clinical research in a meaningful way to funders, reviewers, and other interested parties.

The FDA-NIH working group identified and developed definitions for 37 terms related to innovative clinical study designs, including studies using RWD to generate RWE. In addition, 8 terms are included for reference and FDA and NIH are not seeking comment on these 8 terms. The work serves to clarify terms that are inconsistently used within the scientific community. This initiative was not intended to provide a comprehensive list of clinical research terminology regarding innovative clinical study design, including studies using RWD to generate RWE, but rather to allow for focused collaboration and alignment on terms that are inconsistently used within the scientific community. 

Submitting a Response

FDA and NIH are requesting comment regarding the clinical research terms included in the glossary. Comments can be submitted electronically to, The deadline for submitting comments is June 24, 2024.The website includes a comment form with specific questions to address. Commenters may provide responses to one or all the topics listed in the comment boxes found on the form. Please do not include any proprietary, classified, confidential, or sensitive information in your response.

This RFI is for planning purposes only and should not be construed as a policy, solicitation for applications, or as an obligation on the part of the Government to provide support for any ideas identified in response to it. 


Please direct all inquiries to:

NIH Office of Science Policy