The CONSORT extMontebello-Canada-2003ension for reporting harms outcomes extends 10 checklist items of the CONSORT (2001) checklist. Considerable evidence suggests that reporting of harms-related data from RCTs needs improvement.

Improving Patient Care is a special section within Annals supported in part by the U.S. Department of Health and Human Services (HHS) Agency for Healthcare Research and Quality (AHRQ). The opinions expressed in this article are those of the authors and do not represent the position or endorsement of AHRQ or HHS.

Pictured (left to right): John Ioannidis, David Moher, Ken Schulz, and Doug Altman at the CONSORT group meeting in Montebello, Canada in May 2003.




Available Downloads

The main CONSORT flow diagram should be used.

Document Word Format PDF Format
Checklist n/a Download
Statement & Elaboration n/a Download


Ioannidis JP, Evans SJ, Gotzsche PC, O'Neill RT, Altman DG, Schulz K, Moher D. Better reporting of harms in randomized trials: an extension of the CONSORT statement. Ann Intern Med 2004; 141(10):781-788. PMID: 15545678

Extensions of the CONSORT Statement

The main CONSORT Statement is based on the "standard" two-group parallel design. However, there are several variations to the standard trial methodology, including different design aspects (e.g., cluster), interventions (e.g., herbals) and data (e.g., harms).

To help improve the reporting of these trials the main CONSORT Statement has been extended and modified by members of the CONSORT group for application in these various areas. The resulting CONSORT extensions are presented in this section. This list is, by no means, exhaustive; and work is constantly in progress.

Please note that modifications to the CONSORT checklist or flow diagram that are not developed with the involvement of the CONSORT Group do not have permission to name their work "CONSORT".

Some work, however, has been done to modify the CONSORT Statement without the involvement of the Group. These unofficial extensions of the CONSORT Statement can be found here.


Finding the Appropriate Extension

The table below lists the current official extensions of the CONSORT statement.  You can click on each extension to learn more about it or to explore that extension in the checklist viewer application.


Cluster Trials Herbal Medicinal Interventions CONSORT-PRO
Non-Inferiority and Equivalence Trials Non-Pharmacologic Treatment Interventions Harms
Pragmatic Trials Acupuncture Interventions


N-of-1 Trials Chinese Herbal Medicine Formulas Equity
Pilot and Feasibility Trials  Social and Psychological Interventions Randomised Crossover Trial Reporting
Within Person Trials    
Multi-Arm Parallel-Group Randomized Trials    
Adaptive Designs