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 ......
Article |

Comparing Antibiotics: Statistical Rigor vs Practicality

William C. Blackwelder, PhD
JAMA. 1985;254(23):3311. doi:10.1001/jama.1985.03360230041014.
Text Size: A A A
Published online


To the Editor.—  Lin et al1 have concluded that seven days of ceftriaxone therapy is as effective as ten days of therapy in children with bacterial meningitis, based on the failure to find statistically significant differences in various measures of outcome between two randomized groups of 35 children each. While this conclusion may be correct, the evidence reported is not sufficient to support it. To illustrate, let us consider one of their findings: in each of the two treatment groups, four (11.4%) of 35 children had two or more neurological complications. This result suggests that the two treatments may have a similar effect. However, a 90% confidence interval for the difference between the true percentages is —12.5% to 12.5%; a statistical test at a two-sided 10% significance level would therefore not reject the hypothesis that the true percentages differ by as much as 12.5%. Thus, the study was too


Sign in

Purchase Options

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




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.