The NIH Congressional Justification ("CJ") provides the Senate and House Appropriations Committees detailed estimates and justifications for research and research support activities (infrastructure, administrative, etc.) that NIH would anticipate funding at the President's Budget Request level.
NIH has 27 separate appropriations for which CJ documentation is prepared. Links to this documentation is provided here: Institutes and Centers Congressional Justifications
Please note that the Overview section and the justification for the National Institute of Allergy and Infectious Diseases (NIAID) do not reflect the amendment to the FY 2021 PB request for NIAID released by the Office of Management and Budget on March 17, 2020.