We're unable to sign you in at this time. Please try again in a few minutes.
We were able to sign you in, but your subscription(s) could not be found. Please try again in a few minutes.
There may be a problem with your account. Please contact the AMA Service Center to resolve this issue.
Contact the AMA Service Center:
Telephone: 1 (800) 262-2350 or 1 (312) 670-7827  *   Email: subscriptions@jamanetwork.com
Error Message ......
JAMA Guide to Statistics and Methods |

Interpretation of Clinical Trials That Stopped Early

Kert Viele, PhD1; Anna McGlothlin, PhD1; Kristine Broglio, MS1
[+] Author Affiliations
1Berry Consultants LLC, Austin, Texas
JAMA. 2016;315(15):1646-1647. doi:10.1001/jama.2016.2628.
Text Size: A A A
Published online


This JAMA Guide to Statistics and Methods discusses how to interpret the results of clinical trials that are stopped early based on formal, prespecified stopping rules.

Clinical trials require significant resources to complete in terms of patients, investigators, and time and should be carefully designed and conducted so that they use the minimum amount of resources necessary to answer the motivating clinical question. The size of a clinical trial is typically based on the minimum number of patients required to have high probability of detecting the anticipated treatment effect. However, it is possible that strong evidence could emerge earlier in the trial either in favor of or against the benefit of the novel treatment. If early trial results are compelling, stopping the trial before the maximum planned sample size is reached presents ethical advantages for patients inside and outside the trial and can save resources that can be redirected to other clinical questions. This advantage must be balanced against the potential for overestimation of the treatment effect and other limitations of smaller trials (eg, limited safety data, less information about treatment effects in subgroups).

Sign in

Purchase Options

• Buy this article
• Subscribe to the journal
• Rent this article ?

First Page Preview

View Large
First page PDF preview




Also Meets CME requirements for:
Browse CME for all U.S. States
Accreditation Information
The American Medical Association is accredited by the Accreditation Council for Continuing Medical Education to provide continuing medical education for physicians. The AMA designates this journal-based CME activity for a maximum of 1 AMA PRA Category 1 CreditTM per course. Physicians should claim only the credit commensurate with the extent of their participation in the activity. Physicians who complete the CME course and score at least 80% correct on the quiz are eligible for AMA PRA Category 1 CreditTM.
Note: You must get at least of the answers correct to pass this quiz.
Please click the checkbox indicating that you have read the full article in order to submit your answers.
Your answers have been saved for later.
You have not filled in all the answers to complete this quiz
The following questions were not answered:
Sorry, you have unsuccessfully completed this CME quiz with a score of
The following questions were not answered correctly:
Commitment to Change (optional):
Indicate what change(s) you will implement in your practice, if any, based on this CME course.
Your quiz results:
The filled radio buttons indicate your responses. The preferred responses are highlighted
For CME Course: A Proposed Model for Initial Assessment and Management of Acute Heart Failure Syndromes
Indicate what changes(s) you will implement in your practice, if any, based on this CME course.


Some tools below are only available to our subscribers or users with an online account.

0 Citations

Sign in

Purchase Options

• Buy this article
• Subscribe to the journal
• Rent this article ?

Related Content

Customize your page view by dragging & repositioning the boxes below.

See Also...
Articles Related By Topic
Related Collections
PubMed Articles