Researchers often estimate an association to quantify a possibly causal relationship between an exposure (a treatment, habit, or experience) and an outcome (death, illness, or a continuous measurement). Statistics used to quantify associations include ratios or differences in risks, rates, or means. If the estimated association is causal, these statistics describe the effect of exposure on the outcome. The effect for a population is the average outcome if all were exposed (or at some exposure level) compared with the average outcome if all were not exposed (or at a different level of exposure).1,2
Figure 1. The distributions of final total plasma cholesterol values for treated and control subjects are shown for 3 hypothetical randomized trials of a statin drug. Vertical lines indicate average cholesterol values for each treatment arm; SD, pooled standard deviation for the outcomes; and SMD, standardized mean difference (mean difference divided by pooled SD). The vertical scales for trials 1 and 2 have been compressed compared with the scale for trial 3. To convert total cholesterol to millimoles per liter, multiply by 0.0259.
Figure 2. The distributions of final total plasma cholesterol values for treated and control subjects are shown for 3 hypothetical randomized trials of 3 different statin drugs. Vertical lines indicate average cholesterol values for each treatment arm; SD, pooled standard deviation for the outcomes; and SMD, standardized mean difference (mean difference divided by pooled SD). The vertical scales for trials 4 and 5 have been compressed compared with the scale for trial 6. To convert total cholesterol to millimoles per liter, multiply by 0.0259.
Thank you for submitting a comment on this article. It will be reviewed by JAMA Pediatrics editors. You will be notified when your comment has been published. Comments should not exceed 500 words of text and 10 references.
Do not submit personal medical questions or information that could identify a specific patient, questions about a particular case, or general inquiries to an author. Only content that has not been published, posted, or submitted elsewhere should be submitted. By submitting this Comment, you and any coauthors transfer copyright to the journal if your Comment is posted.
* = Required Field
Disclosure of Any Conflicts of Interest*
Indicate all relevant conflicts of interest of each author below, including all relevant financial interests, activities, and relationships within the past 3 years including, but not limited to, employment, affiliation, grants or funding, consultancies, honoraria or payment, speakers’ bureaus, stock ownership or options, expert testimony, royalties, donation of medical equipment, or patents planned, pending, or issued. If all authors have none, check "No potential conflicts or relevant financial interests" in the box below. Please also indicate any funding received in support of this work. The information will be posted with your response.
Some tools below are only available to our subscribers or users with an online account.
Download citation file:
Web of Science® Times Cited: 11
Customize your page view by dragging & repositioning the boxes below.
More Listings atJAMACareerCenter.com >
Enter your username and email address. We'll send you a link to reset your password.
Enter your username and email address. We'll send instructions on how to reset your password to the email address we have on record.
Athens and Shibboleth are access management services that provide single sign-on to protected resources. They replace the multiple user names and passwords necessary to access subscription-based content with a single user name and password that can be entered once per session. It operates independently of a user's location or IP address. If your institution uses Athens or Shibboleth authentication, please contact your site administrator to receive your user name and password.