Numbers expressed in numerals and numbers expressed in words
NumbersAbbreviations and Acronyms
Reference material:American Psychological Association. (2010).Publication manual of the American Psychological Association(6thed.). Washington, DC: Author.
Use Words for:
Numbers less than 10five participantstwo experimentsCommon fractionsone third of the members of the first groupa two-thirds majorityNumbers that start a sentenceThree different conditions were tested.Fifty college students participated in the study.Universally accepted usageThe Twelve ApostlesFive Pillars of Islam
Use Numerals for:
Numbers 10 and above65items10pointsThe 13thparticipantNumbers in the abstract of the paper (except to start a sentence)Numbers preceding a unit of measurement or time5 cm12lbs3 min6 weeks
Numbers that are used asfractions(except common fractions),decimals, percentages, ratios, and percentiles3/1675% of the populationA ratio of 10:1The 95thpercentile
Numbers that represent time, date, age, scores and points on a scaleLunch is at 12:30 p.m.2-year-oldsA score of 5 on a 10-point scaleA 5-point scale ranging from 1 (not at all) to 5 (extremely)June 13thNumbers that represent a specific place in a seriesCondition 1, Condition 2, Condition 3, etc.Group 5, Group 6, Group 7, etc.Participant 12, Participant 13, Participant 14, etc.
Abbreviations that are pronounced one letter at a time (e.g., APA, DSM, BDI, IQ) are calledinitialismsAbbreviations that are pronounced as a word are called acronyms (e.g., AIDS)Abbreviations should be used sparingly. Use them when:1. The abbreviation is standard and it will not interrupt the reader’s understanding (e.g., AIDS)2. If space can be saved and repetition can be avoided with the use of the abbreviation
Use ofInitialisms& Acronyms
Use the full term the first time, followed immediately by theinitialismor acronym in parentheses(include any necessary citation within the same parentheses, separated by a semi-colon)Human immunodeficiency virus (HIV)Beck Depression Inventory (BDI; Beck, Ward, Mendelsohn, Mock, &Erbaugh, 1961)Do not use the full term in your paper after this point.
My first group of participants would exercise in a peppermint-scented room, after which they would complete the State form of theState-Trait Anxiety Inventory(STAI;Spielberger,Gorsuch, &Lushene, 1970).According to theAmerican Psychological Association(APA), abbreviations can help shorten a paper; however, theAPAsuggests avoiding abbreviations that may confuse your reader.
Latin abbreviations:cf. e.g., i.e., viz., vs. etc.Units of time:s min hr ms nsUnits of measurement:a.m. ˚C cm ˚F g Hz in. kgL m ml mm p.m. V WDo not add ansafter anyabbreviationofa unitofmeasurement
I like many fruits (e.g.,strawberries, grapes, cantaloupe).She defected from the relationship (i.e., she left him).The participants had 5hrto complete the task.Each mouse in Group 2 received 3gof the experimental drug.