Show Summary Details
Page of


Units of Measure

Phil B. Fontanarosa

and Stacy Christiansen

Page of

PRINTED FROM AMA MANUAL OF STYLE ONLINE ( © American Medical Association, 2009. All Rights Reserved. Under the terms of the license agreement, an individual user may print out a PDF of a single chapter of a title in AMA Manual of Style Online for personal use (for details see Privacy Policy and Legal Notice).

date: 25 January 2020

An index generally refers to a quantity derived from a ratio of 2 (or more) measurable quantities and often is used to compare individuals with each other or with normal values. Except for products or quotients representing specific derived SI units of measure (see also , Expressing Unit Names and Symbols, Products and Quotients of Unit Symbols), the ratio of SI units used to create indexes does not represent an SI convention. At first mention in the text, the formula used to calculate the index should be described; thereafter, the numerical value for the index may be given without units

Access to the complete content on AMA Manual of Style requires a subscription or purchase. Public users are able to search the site without a subscription.

Please subscribe or login to access full text content.

If you have purchased a print title that contains an access token, please see the token for information about how to register your code.

For questions on access or troubleshooting, please check our FAQs, and if you can't find the answer there, please contact us.