How to Write a Research Paper in APA Style

Writing a research paper in APA style means satisfying two separate sets of rules at once: the manuscript’s structural organization (what sections exist and in what order) and the American Psychological Association’s specific formatting and citation mechanics layered on top of that structure. APA Style, now in its seventh edition (Publication Manual of the American Psychological Association, 7th ed., 2020, published by APA and confirmed current directly against apastyle.apa.org), is the dominant style in psychology, education, nursing, and the broader social and behavioral sciences, and per APA’s own guidance it is also used in parts of the natural sciences and engineering. This guide walks through the parts of a manuscript that APA governs directly — title page, abstract, the body (usually following an IMRaD structure), in-text citations, and the reference list — plus the mistakes that recur most often when researchers apply APA rules from memory rather than the current edition.

This is a style-specific companion to CASRAI’s broader writing guides. For the general drafting process (what order to write sections in, revision, and submission readiness) see How to Write a Research Paper: Drafting, Style, and Revision. For page-level formatting mechanics that apply across multiple styles (margins, fonts, spacing, headings as a general concept) see Research Paper Format: Margins, Fonts, Spacing, and Style Rules. For how APA compares to MLA, Chicago, Vancouver, AMA, and IEEE, and how to choose between them, see Citation Styles and Referencing Formats. This guide is the one that goes deep specifically on APA’s own rules, in one place.

Student Papers vs. Professional Manuscripts: Two Different Rule Sets

Before formatting anything, confirm which APA track applies — the seventh edition explicitly distinguishes student papers (coursework, theses, dissertations submitted under an institution’s own requirements) from professional papers (manuscripts submitted to a journal for publication). The two differ in real, checkable ways: student papers by default omit a running head and an abstract unless an instructor or institution specifically requests them; professional papers require both a running head and an author note, and are expected to include an abstract. A researcher who copies a professional-manuscript title page for a course assignment, or vice versa, has made a real formatting error, not a stylistic preference — check which track your instructor, institution, or target journal expects before you start.

The Title Page

Both title-page formats share a centered, bold title placed roughly three to four lines from the top of the page, in title case, followed by the author name(s) and institutional affiliation, also centered. A page number (“1”) appears in the top-right corner of every page, including the title page. Beyond that shared baseline, the two tracks diverge:

Student papers: title, author name(s), affiliation, course number and name, instructor name, and the assignment due date — all centered. No running head unless the instructor or institution asks for one.
Professional papers: title, author name(s), affiliation(s) (the institution where the research was actually conducted, which is not always the same as the author’s current institution), an Author Note (a centered, bold “Author Note” label with left-aligned content below it — typically ORCID iDs, disclosures, and contact information), and a running head in all capitals, left-aligned in the page header.

A common error: including a running head on a student paper “to be safe,” or omitting the author note on a professional submission. Neither is correct under the seventh edition’s default rules — match the track that actually applies.

The Abstract

Per APA’s own Abstract and Keywords Guide (2020), an abstract is not typically required for student papers — confirm with the instructor whether one is expected. Where an abstract is required (essentially always for a professional manuscript), APA’s rules are specific:

Length: limited to 250 words. Some journals or instructors set a tighter limit — check the target’s own instructions for authors, since a journal’s house limit always overrides the general APA default.
Placement: the second page of the manuscript, immediately after the title page.
Format: the label “Abstract” is centered and bold on the first line of the page; the abstract text begins one line below, is not indented, is written as a single unbroken paragraph, and is double-spaced like the rest of the paper.
Content: APA recommends covering, usually in one to two sentences each — the research problem or question, key context from the literature, the hypothesis or hypotheses, the methods used (study design, sample, and sample size), the results, and the implications of the findings.
Keywords: three to five words, phrases, or acronyms, placed one line below the abstract under an italicized (not bold) “Keywords:” label, with the keywords themselves lowercase (except proper nouns), not italicized, comma-separated, and in any order.

The Body: IMRaD and APA’s Heading System

APA does not itself invent the IMRaD structure (Introduction, Methods, Results, and Discussion) — that convention is broader than any single citation style and is shared across most empirical social- and behavioral-science reporting — but APA’s seventh edition does specify exactly how a manuscript’s internal headings should look once that structure (or any other section structure) is chosen. Getting the heading levels right is a distinct, separately-graded formatting skill from getting the section order right, and APA’s five heading levels are precise enough to check mechanically:

Level	Format	Example
1	Centered, Bold, Title Case — text starts a new paragraph below	Method
2	Flush Left, Bold, Title Case — text starts a new paragraph below	Participants
3	Flush Left, Bold Italic, Title Case — text starts a new paragraph below	*Recruitment*
4	Indented, Bold, Title Case, ending in a period — text continues on the same line	Inclusion criteria. Text continues here…
5	Indented, Bold Italic, Title Case, ending in a period — text continues on the same line	*Age range.* Text continues here…

Most papers use only two or three of these levels — a short IMRaD paper rarely needs level 4 or 5. The most common formatting mistake here is treating heading level as a synonym for font size rather than for this specific centered/flush-left/indented and bold/bold-italic combination; a heading one level “off” from what its position in the outline calls for is a real, checkable APA error, not a stylistic judgment call.

Manuscript-Wide Formatting Mechanics

These apply to the whole document, not just specific sections:

Margins: 1 inch on every side of every page (Publication Manual, 7th ed., Section 2.22). Dissertations or theses may specify a different binding margin per an institution’s own requirements — that institutional rule overrides the general APA default.
Font: APA 7 permits a defined set rather than a single mandated font — sans-serif options include 11-point Calibri, 11-point Arial, or 10-point Lucida Sans Unicode; serif options include 12-point Times New Roman, 11-point Georgia, or 10-point Computer Modern (the LaTeX default). Whichever is chosen must be used consistently throughout the body text (figures, code samples, and footnotes carry their own separate conventions).
Line spacing: double-space the entire paper — abstract, body text, block quotations, table and figure numbers/titles/notes, and the reference list all take double-spacing, with no extra blank line inserted between paragraphs. Table interiors and figure images are the exception and may use single, 1.5, or double spacing for readability.
Paragraph indentation: the first line of every paragraph is indented 0.5 inch, with the exception of the abstract (not indented) and block quotations (indented as a whole block — see below).

For the fuller cross-style treatment of these same mechanics (how APA’s specific values compare to MLA’s and Chicago’s), see Research Paper Format: Margins, Fonts, Spacing, and Style Rules.

In-Text Citations: The Author-Date System

APA uses an author-date citation system: a brief in-text citation points the reader to a full entry in the reference list, and the two must correspond exactly — every source cited in text must appear in the reference list, and every reference-list entry must be cited somewhere in the text. There is no legitimate reason for the two lists to diverge; a reference with no matching in-text citation, or a citation with no matching reference, is one of the most common and most easily caught manuscript errors.

Both of the following forms are standard APA usage:

Parenthetical citation: the citation sits in parentheses, separate from the sentence’s grammar — e.g., “…effect sizes were consistently underreported (Smith, 2023).”
Narrative citation: the author’s name is part of the sentence itself, with only the year in parentheses — e.g., “Smith (2023) found that effect sizes were consistently underreported.”

APA’s general citation principles also call for citing primary sources over secondary sources wherever the primary source is actually available, and for citing only sources genuinely consulted — a citation to a work the author has not actually read (picked up secondhand from another paper’s reference list) is a documented, if under-discussed, integrity issue in scholarly writing, not just a style nicety.

Direct Quotations and Block Quotes

APA requires a page number (or paragraph number for unpaginated sources) alongside the author and year whenever a source is quoted directly — this is one of the more commonly skipped elements, since a paraphrase only requires author and year.

Quotations under 40 words stay inline, enclosed in double quotation marks, with the citation giving author, year, and page — e.g., (Smith, 2023, p. 25).
Quotations of 40 words or more are formatted as a block quotation: no quotation marks, started on a new line, the whole block indented 0.5 inch from the left margin, double-spaced like the rest of the paper, with the citation placed in parentheses after the quotation’s final punctuation (or just the page number in parentheses, if the author and year were already given in a narrative lead-in sentence).

Multiple Authors and “et al.”

APA 7 changed this rule from the sixth edition in a way that trips up researchers working from an older habit: for a source with three or more authors, APA 7 abbreviates to the first author’s surname plus “et al.” starting from the very first citation — not just on the second and later mentions, which was the sixth-edition rule. In the reference list itself, up to 20 authors are listed in full; for 21 or more authors, list the first 19, insert an ellipsis, then the final author’s name (no “et al.” in the reference list). For the same rule compared across MLA, Chicago, and Vancouver/AMA, see CASRAI’s dedicated Et Al. Citation Rules guide.

The Reference List

The reference list is a separate page (or pages) at the end of the manuscript, headed “References,” centered and bold, at the top of a new page. APA’s formatting rules for the list itself are mechanical and checklist-verifiable:

Alphabetical order: entries are ordered alphabetically by the first element of the reference — usually the surname of the first author. Where no author exists, the work is alphabetized by its title instead.
Hanging indent: every entry uses a 0.5-inch hanging indent — the first line of each reference sits flush left, and every subsequent line of that same entry is indented 0.5 inch. This is one of the most frequently missed formatting details, since word processors don’t apply it automatically.
Double-spacing: the whole list is double-spaced, with no extra blank line inserted between entries.
DOIs and URLs: presented as either a live hyperlink (blue, underlined — the typical hyperlink default) or as plain, non-underlined text; either is acceptable as long as the choice is applied consistently across the whole list.

The exact fields and punctuation inside a single reference entry vary by source type (journal article, book, dataset, webpage, preprint, and so on) — that level of per-source-type detail is outside this guide’s scope. CASRAI covers it directly for two of the most common non-trivial cases: How to Find, Cite, and Use a DOI (with a full worked APA reference-list example for a DOI-bearing journal article) and How to Cite a Dataset (for data and software outputs, which follow different rules than a standard journal article).

Common APA Pitfalls, Specifically for Researchers

These recur often enough in editorial-office and instructor feedback to be worth calling out directly, distinct from the generic “how to cite” mistakes a consumer-facing citation tool would flag:

Applying sixth-edition “et al.” rules from memory. The three-or-more-authors-from-the-first-citation rule (above) is the single most common APA formatting error among researchers who learned APA under the sixth edition and never re-checked the seventh edition’s change.
Treating heading level as a font-size choice rather than the specific centered/flush-left/indented, bold/bold-italic combination each level actually requires (see the heading table above).
Including a running head on a student paper, or omitting the author note on a professional manuscript — matching the wrong track’s title-page requirements to the actual submission context.
Forgetting the page number on a direct quotation. A paraphrase needs only author and year; a direct quotation always needs a page (or paragraph) number too, in both parenthetical and narrative citation forms.
Letting the reference list and in-text citations drift out of sync during revision — a source cut from the text but left in the reference list (or added to the text late and never added to the list) is one of the most common issues editorial offices flag before a manuscript even reaches peer review.
Skipping the hanging indent on the reference list, or applying it inconsistently — a word-processor default paragraph does not automatically produce APA’s required 0.5-inch hanging indent; it has to be applied as a specific paragraph-formatting rule.
Assuming a field’s typical style is a fixed rule. A field-default is not a requirement — many psychology-adjacent journals don’t actually use APA, and the target journal’s own instructions for authors always override the general field convention. Confirm the required style before drafting, not after.

Frequently Asked Questions

Do I need an abstract in APA style?

Not automatically for a student paper — confirm with your instructor or institution. An abstract is expected for essentially all professional manuscripts submitted for publication, limited to 250 words unless the target journal sets a different limit.

What’s the difference between APA 6 and APA 7 for citations?

The most consequential change for everyday citing is the “et al.” threshold: APA 7 abbreviates any source with three or more authors to the first author plus “et al.” starting from the very first citation, where APA 6 spelled out three-to-five authors on first citation and only shortened afterward. APA 7 also updated the recommended font list and clarified the student-vs-professional paper distinction, among other changes.

Is a running head required in APA 7?

Only for professional manuscripts submitted for publication. Student papers do not include a running head under the seventh edition’s default rules unless an instructor or institution specifically asks for one.

How do I cite a source with no individual author in APA style?

Use the organization or group responsible for the work as the author (e.g., a funder, government agency, or professional association), and alphabetize the reference-list entry by that organization’s name. If genuinely no author or organization can be identified, the title moves into the author position and the entry is alphabetized by title instead.

Does APA require a specific citation manager?

No — APA specifies the citation format itself, not the tool used to produce it. Reference-management software (Zotero, EndNote, Mendeley, and similar tools) can generate APA-formatted citations, but every automated citation should still be checked against the current edition’s rules before submission, since style-manager output is not always current with the latest edition’s changes.

Related CASRAI Guides

How to Write a Research Paper: Drafting, Style, and Revision — the section-by-section drafting process this guide’s formatting rules apply to.
Research Paper Format: Margins, Fonts, Spacing, and Style Rules — page-level formatting mechanics compared across APA, MLA, and Chicago.
Citation Styles and Referencing Formats: A Practical Overview — how to choose between APA, MLA, Chicago, Vancouver, AMA, and IEEE.
Et Al. Citation Rules: APA, MLA, Chicago & Vancouver/AMA — the full cross-style “et al.” threshold table.
How to Find, Cite, and Use a DOI — worked APA reference examples for DOI-bearing sources.
Scholarly Writing hub — the full CASRAI cluster on manuscript preparation, submission, and academic writing craft.