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AMA Manual of Style (10th ed.) : A Guide for Authors and Editors

AMA Manual of Style Committee

Publisher:
Oxford University Press
Print Publication Date:
Mar 2007
Print ISBN-13:
9780195176339
Published to AMA Manual of Style:
Apr 2009
DOI:
10.1093/jama/9780195176339.001.0001
© American Medical Association
Contents

Decimal Format

Chapter:
Units of Measure
Author(s):

Cheryl Iverson,

Stacy Christiansen,

Annette Flanagin,

Phil B. Fontanarosa,

Richard M. Glass,

Brenda Gregoline,

Stephen J. Lurie,

Harriet S. Meyer,

Margaret A. Winker,

Roxanne K. Young

18.4.2 Decimal Format

The decimal format is recommended for numbers used with units of measure. Numerical values less than 1 require placement of 0 before the decimal marker.

Preferred:

0.123

Avoid:

.123

However, certain statistical values, such as α levels and P values, should be reported without the use of 0 before the decimal marker. (See 19.7.1, Numbers and Percentages, Forms of Numbers, Decimals; and 20.9, Study Design and Statistics, Glossary of Statistical Terms.)

The sample size was based on detecting a 10% difference in the primary outcome measure, using a 2-sided α level of .05.

Statistical significance was defined as P < .01.

Fractions should not be used with SI units.

Preferred:

2.5 kg

Avoid:

2½ kg

Mixed fractions occasionally are used in text to indicate less precise measurements and most commonly involve units of measure representing time.

After more than 7½ years of investigation, the effort to develop a new vaccine was abandoned.

The decimal format also could be used:

After more than 7.5 years of investigation, the effort to develop a new vaccine was abandoned.