APA 7 style mechanics: writing and presentation rules

What style mechanics covers

Style mechanics are the small, repeated decisions that make academic writing consistent: capitalization, italics, punctuation, abbreviations, numbers, units, and statistical symbols. These rules do not replace clear reasoning, but they help readers recognize titles, quantities, findings, and specialized terms without having to interpret each formatting change.

This guide focuses on the presentation rules in Chapter 6 of APA Style. All examples are illustrative and demonstrate one decision at a time.

How to use this guide

Apply these rules throughout the paper, not only in the main text. Review the title page, headings, tables, figures, and appendices because each may contain titles, abbreviations, numbers, or symbols.

If your instructor, institution, or publisher provides a specific style requirement, follow it consistently across the paper. Do not mix capitalization, decimal, or abbreviation conventions between sections.

Capitalization

Capitalize the first word of a complete sentence and the first word after a colon when what follows is a complete sentence. Preserve the established capitalization of proper names, institutions, courses, and trade names.

APA Style uses title case for the title of your paper, its headings, titles of works mentioned in the text, periodical titles, and table and figure titles. In title case, capitalize the first word, the first word of a subtitle, major words, and words of four letters or more.

Strategies for Revising an Academic Paper

Use sentence case for titles of articles, books, reports, webpages, and other works in reference entries. Capitalize the first word, the first word after a colon, and proper nouns:

Strategies for revising an academic paper: A classroom study

Capitalize a noun followed by a number or letter when it identifies a specific part of a series:

• Table 2
• Figure 4
• Appendix A
• Research Question 3

Keep page and paragraph lowercase before a number: page 8, paragraph 4.

Do not capitalize generic names of theories, methods, diseases, treatments, experimental groups, or variables. Retain a proper name within such a term, as in Alzheimer's disease or Pavlovian conditioning.

The headings guide shows how capitalization works together with alignment, bold, and italics at each level.

When to use italics

Use italics for:

• a key term when it is defined for the first time;
• titles of books, reports, webpages, and other stand-alone works;
• periodical titles and volume numbers in references;
• letters used as statistical symbols or algebraic variables;
• verbal anchors of a scale;
• genus, species, and variety names;
• the first use of an unfamiliar word from another language.

Examples:

Layered revision means reviewing a different aspect of a paper during each pass.

Responses ranged from 1 (never) to 5 (always).

The group obtained a mean score of 18.40 (M = 18.40, SD = 2.15).

Italicize a key term only once. Do not italicize et al., Greek letters, chemical names, an abbreviation merely because it is shortened, or an entire sentence simply to add emphasis.

Punctuation after an italicized element remains in standard type unless it belongs to the element, such as a question mark within a book title.

How to use quotation marks

Exact words from a source follow the direct quotation rules. Outside quotations from sources, use double quotation marks to:

• present a letter, word, or sentence as a linguistic example;
• reproduce instructions given to participants;
• introduce an ironic, coined, or labeled expression on its first use;
• identify the title of an article or chapter in the text.

The available responses were “yes” and “no.”

The initial label was “rapid review”; later references used rapid review without quotation marks.

Do not place quotation marks around a key term merely to emphasize it. Italicize the term on its first use if you are defining it. Do not use quotation marks to distance yourself vaguely from a word without explaining the intended meaning.

Place periods and commas inside closing quotation marks. Place colons and semicolons outside unless they are part of the quoted material.

Parentheses and square brackets

Use parentheses for independent supplementary information, in-text citations, abbreviation definitions, lettered lists within a sentence, mathematical groupings, statistical values, and degrees of freedom.

The questionnaire was administered in two sessions (see Table 3).

The Writing Strategies Scale (WSS) was used.

The stages were (a) planning, (b) drafting, and (c) revising.

The difference was statistically significant (p = .031).

Avoid parentheses within parentheses. When information already appears in parentheses, use square brackets for the second level:

(Writing Strategies Scale [WSS]; Rojas, 2023)

Square brackets also contain confidence interval (CI) limits and material added to a direct quotation:

95% CI [0.18, 0.74]

“Revision [of the content] began after the draft was complete” (Mora, 2024, p. 36).

Mathematical grouping follows a different sequence: parentheses first, then square brackets, and then braces if another level is needed: {[( )]}.

Punctuation in academic writing

APA Style recommends one space after periods, commas, colons, and semicolons. Do not insert spaces around a colon in a ratio, as in 1:4.

Use a serial comma before the final item in a series of three or more items:

height, width, and depth

Use a semicolon to separate multiple citations in one set of parentheses:

(Alvarez, 2021; Mora & Rivers, 2023; Torres et al., 2024)

A semicolon can also separate groups that already contain commas. Use a colon after a complete introductory clause to provide an explanation or list:

Revision had three stages: content, structure, and format.

Do not use a colon after an incomplete introduction:

The process included planning, drafting, and revising.

Use an en dash without spaces for page, date, and percentage ranges: pp. 24–29, 2021–2024, 18%–20%.

Abbreviations and acronyms

An abbreviation is useful when it prevents cumbersome repetition and remains clear to readers. Do not invent an acronym for a phrase that appears only once or twice. As a general guide, an author-defined abbreviation should appear at least three times.

Write the full term on first use and place the abbreviation in parentheses:

The Writing Strategies Scale (WSS) contains 18 items. The WSS was administered twice.

When the full term first appears inside parentheses, use square brackets for the abbreviation:

(Writing Strategies Scale [WSS]; Rojas, 2023)

After defining an abbreviation, use it consistently. Do not alternate between the term and the abbreviation without a reason. Define abbreviations again within each table and figure so that the element can be understood independently.

Common measurement and statistical symbols do not need definitions. Define abbreviations such as ANOVA, RMSEA, and CI the first time they appear unless they are already standard terms for the intended readers.

Form the plural of most abbreviations by adding a lowercase s without an apostrophe, as in URLs and DOIs. Do not add a plural ending to measurement symbols: 3 cm, not 3 cms.

Numbers in numerals or words

As a general APA rule, spell out zero through nine and use numerals for 10 and above:

three groups, nine responses, 12 participants, 25 questions

Use numerals even below 10 for:

• measurements: 5 cm;
• decimal quantities: 0.48;
• mathematical functions, proportions, and ratios: 3 times, 2:1;
• percentages and percentiles: 7%, 5th percentile;
• time, dates, ages, scores, and money: 4 days, 8 years, 3 points, $5;
• a position in a numbered series: Table 2, Question 4.

Spell out a number that begins a sentence, title, or heading. Reword the sentence when that avoids a long written number.

Forty-eight participants completed the second session.

Spell out common fractions, such as two thirds of the sample. Apply the same general threshold to ordinal and cardinal numbers.

Decimal numbers

Place a zero before a decimal when the value can exceed 1:

d = 0.70

0.48 cm

Omit the zero when the statistic cannot exceed 1, such as a correlation, proportion, or significance level:

r = −.43, p = .028

Round as much as possible without losing necessary precision. APA generally recommends two decimal places for correlations, proportions, and inferential statistics such as t, F, and chi-square. One decimal place is often sufficient for means and standard deviations calculated from integer scales.

Report exact p values to two or three decimal places. Write values below .001 as p < .001.

Use a decimal point consistently in statistical values. Do not alternate decimal separators within the text or between the text and tables.

Percentages and units of measurement

Use the percent symbol with a numeral and the word percentage when no number appears:

Thirty-six percent of the sample completed the activity.

The percentage of correct responses was calculated.

In ordinary text, the numeral and percent sign appear together: 36%. Repeat the symbol across a range: 18%–20%.

With a numeric value, use the recognized symbol or abbreviation for a unit. Without a value, spell out the unit:

4 cm, 30 kg, 12 min, 6 hr, 22 °C

distance in centimeters

Place a space between the number and unit. An angle is an exception: 45°. Do not pluralize measurement abbreviations or add a period.

APA journals use the metric system. If an instrument records a nonmetric unit, follow it with the rounded metric equivalent, as in 3 ft (0.91 m).

Statistical symbols

Common statistical symbols do not need definitions:

Symbol	Meaning
M	Sample mean
SD	Standard deviation
N	Total sample size
n	Group or subsample size
p	Probability or significance value
r	Sample correlation
t, F	Test statistics
α, β, χ²	Greek statistical symbols

Italicize Latin letters used as statistical symbols, including M, SD, N, n, p, r, t, and F. Keep Greek letters such as α, β, and χ² in standard type.

Use the word in narrative prose and the symbol when reporting a value:

The means increased in the second group.

The second group obtained a higher mean (M = 7.74).

Do not mix notation systems. If your journal or discipline uses a different recognized notation, identify it when necessary and use it consistently in the text, tables, and figures.

How to report statistics in the text

Choose the format that makes comparison easiest. APA offers this starting point:

• three or fewer numbers: first try a sentence;
• four to 20 numbers: first consider a table;
• more than 20 numbers: first consider a figure.

These counts are not automatic requirements. The final choice should help readers understand the results. When a table already presents descriptive statistics, do not repeat all of them in the paragraph. Refer to the table and emphasize only the values needed to interpret the finding.

An inferential result should provide enough information to identify the test, degrees of freedom, obtained value, significance, and, when relevant, effect size and confidence interval.

Illustrative example:

The group that reviewed the paper in two stages scored higher (M = 24.6, SD = 3.1) than the single-review group (M = 21.8, SD = 4.0), t(58) = 2.43, p = .018, d = 0.63, 95% CI [0.11, 1.14].

A confidence interval must state its level and enclose the limits in square brackets. When several measures appear in the same order, make clear which value belongs to each result.

Special characters and mathematical symbols

Use the correct character for each operation. A minus sign is not a hyphen. Place a space on both sides of an operator:

a + b = c

z − y = x

Do not place a space between a negative sign and its value: −8.25. Use the multiplication sign ×, not the letter x, for an operation or interaction.

Insert subscripts and superscripts with your word processor's formatting controls. Do not imitate them by manually reducing the font size. Check Greek letters, mathematical signs, and uncommon characters before submitting or converting the file.

Short equations can remain within a sentence. Display complex equations and equations that need a number on a separate line. Number displayed equations consecutively and place the number in parentheses near the right margin. The guide to equations in APA Style explains their placement and punctuation.

Checklist

Before submitting, check that:

• capitalization matches the language of the paper;
• italics and quotation marks have a recognizable purpose;
• square brackets replace nested parentheses where required;
• each author-defined abbreviation is introduced and used consistently;
• numbers below 10 follow APA exceptions for measurements and statistics;
• decimal separators remain consistent;
• percentages and units have the correct spacing;
• statistical symbols use italic or standard type according to their function;
• the text does not repeat a table's statistics unnecessarily;
• mathematical signs, subscripts, and superscripts use the correct characters;
• writing and punctuation remain consistent throughout the paper.