- ClinicalTrials.gov Statistics
- Who Uses ClinicalTrials.gov
- Related Journal Publications
- Learn More
ClinicalTrials.gov is a Web-based resource that provides patients, their family members, health care professionals, researchers, and the public with easy access to information on publicly and privately supported clinical studies on a wide range of diseases and conditions. The Web site is maintained by the National Library of Medicine at the National Institutes of Health (NIH). Information on ClinicalTrials.gov is provided and updated by the sponsor or principal investigator of the clinical study. Studies are generally submitted to the Web site (that is, registered) when they begin, and the information on the site is updated throughout the study. In some cases, results of the study are submitted after the study ends. This Web site and database of clinical studies is commonly referred to as a "registry" and "results database."
ClinicalTrials.gov includes information about medical studies in human volunteers. Most of the records in ClinicalTrials.gov describe clinical trials (also called interventional studies). A clinical trial is a research study in which human volunteers are assigned to interventions (for example, a medical product, behavior, or procedure) based on a protocol (or plan) and are then evaluated for effects on biomedical or health outcomes. ClinicalTrials.gov also includes records describing observational studies and programs providing access to investigational drugs outside of clinical trials (expanded access).
ClinicalTrials.gov does not contain all clinical studies conducted in the United States because not all studies are required by law to be registered, such as observational studies and trials that do not study a drug, biologic, or device (see FDAAA 801 Requirements for more information). However, the rate of registration has increased over time as more policies and laws requiring registration have been enacted and as more sponsors and investigators voluntarily register their studies.
ClinicalTrials.gov was made available to the public on February 29, 2000 and the results database was released in September 2008. Once a study is registered on the site, it is not removed. The full history of changes made to a record can be accessed by viewing the archival version of the record on the ClinicalTrials.gov archive site.
Read a complete account of the development and expansion of ClinicalTrials.gov in response to changes in policies and laws on the History, Policies, and Laws page.
Searching ClinicalTrials.gov does not require registration or personal identification. Because ClinicalTrials.gov is a government Web site, it does not host, or receive funding from, advertising or the display of commercial content.
ClinicalTrials.gov receives more than 98 million page views per month and 64,000 unique visitors daily (as of July 2013)
The following statistics are updated nightly:
- ClinicalTrials.gov currently contains 165,721 study records. 42,320 studies are recruiting participants. Studies are sponsored by NIH, other Federal agencies, nonprofit organizations, and private industry.
- Studies listed in the database are conducted in all 50 States and in 186 countries.
For more statistics, charts, and maps related to ClinicalTrials.gov, see the Trends, Charts, and Maps page.
Who Uses ClinicalTrials.gov
The main users of the site are patients, their families and caregivers, health care professionals, clinical researchers, and study record managers.
They use ClinicalTrials.gov to:
- Search for open clinical studies (See Search of: Open Studies)
- Browse studies by category or location (See Studies by Topic)
- Search for studies that include results (See Search of: Studies With Results)
Clinical researchers also use the site to stay current on developments in their field of interest, find collaborators, and help identify unmet research needs. Other researchers may use the site to compile information on the research being conducted in a particular area to support the development of practice guidelines or reviews of completed research. In addition, clinical researchers or their study record managers must register their studies and submit study results to ClinicalTrials.gov using a Web-based system called the Protocol Registration System. For more information, see:
- Why Should I Register and Submit Results?, How to Register Your Study, and How to Submit Your Results
- Brochure on registering and submitting results for sponsors and investigators
Related Journal Publications
- Zarin DA, Tse T, Williams RJ, Califf RM, Ide NC. The ClinicalTrials.gov results database—update and key issues. N Engl J Med. 2011;364(9):852-60. [Full Text]
- Tse T, Williams RJ, Zarin DA. Reporting "Basic Results" in ClinicalTrials.gov. Chest. 2009;136(1):295-303. [Full Text]
- Zarin DA, Tse T. Moving towards transparency of clinical trials. Science. 2008;319(5868):1340-42. [Full Text (author manuscript)]
- Zarin DA, Ide NC, Tse T, Harlan WR, West JC, Lindberg DA. Issues in the registration of clinical trials. JAMA. 2007;297(19):2112-20.
- Zarin DA, Tse T, Ide NC. Trial registration at ClinicalTrials.gov between May and October 2005. N Engl J Med. 2005 Dec 29;353(26):2779-87. [Full Text]
ClinicalTrials.gov Wins the Innovations in American Government Award
In 2004 ClinicalTrials.gov was cited by the Ash Center for Democratic Governance and Innovation at the Harvard Kennedy School as "a successful model for the creation and maintenance of a system that processes and presents large amounts of specialized information to a wide range of users" and was selected as one of five award winners. The Innovations in American Government Awards is the nation's preeminent program devoted to recognizing and promoting excellence and creativity in the public sector. The program highlights exemplary models of government innovation and advances efforts to address the nation's most pressing public concerns.
- ClinicalTrials.gov Innovations in American Government Awards Site
- National Institutes of Health's ClinicalTrials.gov Web Site Wins Prestigious Award - National Institutes of Health Press Release, 7/28/04
For more information including interview requests, please contact the National Library of Medicine Office of Communications and Public Liaison Director Kathy Cravedi (firstname.lastname@example.org or 301.496.6308) or Deputy Director Melanie Modlin (email@example.com or 301.496.7771).
- ClinicalTrials.gov Background: The site's purpose; who supplies study record data; how to use the site
- History, Policies, and Laws: A timeline of events, laws, and policies affecting the creation and development of the site
- Selected Publications: Scholarly publications about ClinicalTrials.gov and clinical research
- Trends, Charts, and Maps: Featured statistics of general interest in narrative and graphic form
- FDAAA 801 Requirements: Information on registration and results submission requirements under U.S. law for clinical researchers