Parenthetical Citation

Parenthetical citation is the general term for an in-text citation given inside parentheses, directly in the running sentence, rather than through a superscript footnote/endnote marker or a bracketed reference number. What sits inside the parentheses — an author and a year, an author and a page number, or some combination — is set by whichever citation style governs the document, not by any single universal rule. The one constant across styles is the container itself: the identifying information a reader needs to find the full source in the reference list or bibliography appears directly in parentheses in the text, not as a pointer to a separate numbered note.

Parenthetical vs. Narrative Citations

Within author-date and author-page styles, a citation can be built two ways. A parenthetical citation places the author’s name inside the parentheses along with the date or page: “Falsely balanced coverage can distort readers’ perception of expert consensus (Koehler, 2016).” A narrative citation instead works the author’s name into the sentence itself, with only the date (or page) left in parentheses: “Koehler (2016) found that falsely balanced coverage distorts readers’ perception of expert consensus.” Both are legitimate, stylistically interchangeable choices in APA, MLA, and Chicago’s author-date system — which one to use is a sentence-level judgment call (does the source or the finding deserve the emphasis of being named in the sentence?), not a formatting error either way.

How the Exact Format Varies by Style

The three major styles that use parenthetical citations at all build the parentheses differently. CASRAI’s Citation Styles and Referencing Formats guide covers the full field-by-field comparison across all major styles, including the numbered systems that don’t use parentheses at all; this entry focuses on the parenthetical mechanics themselves.

• APA (7th edition, American Psychological Association): author-date. Author surname and publication year, separated by a comma — (Koehler, 2016). For a source with two authors, both surnames joined by an ampersand: (Smith & Jones, 2019). For three or more authors, the first author’s surname plus “et al.”: (Smith et al., 2019). When quoting directly, APA requires a page (or paragraph, for unpaginated sources) number as well, added after a second comma: (Koehler, 2016, p. 42). See CASRAI’s Et Al. Citation Rules guide for the exact author-count thresholds across styles.
• MLA (9th edition, Modern Language Association): author-page, not author-date. Author surname and the page number the material appears on, with no comma and no “p.” abbreviation between them — (Smith 8). If the author’s name is already given in the sentence, only the page number stays in parentheses: Smith argues the opposite (8). MLA specifically instructs writers not to estimate or invent a page number for a source that doesn’t have one (many web sources) — omit the number rather than guess.
• Chicago author-date system (18th edition, University of Chicago Press): author and year, no comma between them, with a page number optionally added after a comma — (Smith 1998, 45). This is one of two Chicago citation systems, and it’s the only one that’s parenthetical (see below).

Chicago’s Other System Is Not Parenthetical

Chicago is the one style covered above that offers a genuine choice between two citation systems, and only one of them is parenthetical. The notes-bibliography system — Chicago’s traditional format for history and much of the humanities — uses a superscript number in the text pointing to a footnote or endnote, not a parenthetical author-date citation. A manuscript following Chicago notes-bibliography style has no parenthetical citations in the running text at all; the citing information lives entirely in the notes. Which of the two systems applies is set by the field or the publisher’s instructions, not by writer preference — CASRAI’s Citation Styles and Referencing Formats guide covers when each Chicago system is expected.

Numbered Citations Are Not Parenthetical Citations

Vancouver/ICMJE (used in biomedicine), AMA, and IEEE all cite sources with a number rather than an author name — a superscript numeral, or a number inside square brackets or parentheses, such as [3] or (3). Even when that number happens to be enclosed in parentheses, it is not what this entry means by “parenthetical citation”: the parentheses (or brackets) contain only a pointer to an entry in a separately numbered reference list, not the author/date/page information itself. The defining feature of a parenthetical citation is that the identifying information — who, and when or where — is legible directly in the text, without having to look anything up by number first.

Common Mistakes

• Missing the page number on a direct quotation. APA, MLA, and Chicago (in both its systems) all require a page number — or equivalent locator, such as a paragraph number for unpaginated web content — for a direct quotation, even when a paraphrase of the same source would not need one. Citing only the author and year for a quoted passage under APA, or only the author’s name for a quoted passage under MLA, is incomplete under every major style’s own rules, not a stylistic shortcut.
• Inconsistent formatting within one document. Mixing parenthetical formats mid-manuscript — switching between (Smith, 2019) and (Smith 2019), or between comma-separated and non-comma-separated author-date pairs — is the single most common error a copyeditor or reviewer flags, and it usually happens when a writer pulls citations from sources originally formatted in a different style, or switches reference-manager citation styles partway through drafting without re-checking every existing in-text citation.
• Treating parenthetical and narrative forms as formatted the same way. A narrative citation still needs the date (or page) in parentheses immediately after the author’s name is used in the sentence — dropping the parenthetical date entirely because the author was already named narrows the citation, it doesn’t remove the requirement for one.
• Guessing a page number that doesn’t exist. For sources without stable pagination (most web pages, some e-books), MLA and APA both direct writers to omit the page/locator rather than invent one, or to use a paragraph or section heading as the locator where the source supports it.
• Placing punctuation on the wrong side of the citation. In all three parenthetical styles covered here, the sentence’s closing punctuation goes after the closing parenthesis, not before it — (Koehler, 2016)., not (Koehler, 2016.) — except when citing a block quotation, where the citation follows the final punctuation of the quoted text instead.

Worked Examples

Example 1 (APA, parenthetical, paraphrase). “Falsely balanced news coverage can distort the public’s perception of expert consensus on an issue (Koehler, 2016).” No page number is required because the sentence paraphrases the source rather than quoting it directly.

Example 2 (MLA, parenthetical, direct quote). A student writes: “Here’s a direct quote” (Smith 8). The author surname and the exact page the quotation appears on are both required; no comma or “p.” separates them.

Counter-example. A biomedical manuscript that cites sources as Prior work has shown this effect [3,7]. is using a numbered citation system (consistent with Vancouver/ICMJE, common in clinical and biomedical journals), not a parenthetical citation — the bracketed numbers point to a reference list ordered by first mention, and carry no author or date information on their own. Describing this manuscript’s in-text citations as “parenthetical” would be a category error, even though the numbers happen to sit inside brackets rather than out in the open.

Related CASRAI Content

• Citation Styles and Referencing Formats: A Practical Overview — the full style-selection comparison across APA, MLA, Chicago, Vancouver/ICMJE, AMA, and IEEE.
• Et Al. Citation Rules: APA, MLA, Chicago & Vancouver/AMA — exactly when “et al.” replaces additional author names in each style.
• Research Paper Format: Margins, Fonts, Spacing, and Style Rules — the page-level formatting mechanics that sit alongside citation style in the same style manual.
• How to Write a Research Paper: Drafting, Style, and Revision — where citation decisions fit into the broader drafting process.
• How to Find, Cite, and Use a DOI — full worked reference-list (not in-text) examples across APA, MLA, Chicago, Vancouver, and IEEE.

References

• American Psychological Association, Publication Manual of the American Psychological Association, 7th ed. (2020) — Author-date citation system, and Direct quotation of material with page numbers, apastyle.apa.org.
• Modern Language Association, MLA Handbook, 9th ed. (2021) — In-text citations: the basics, style.mla.org.
• University of Chicago Press, The Chicago Manual of Style, 18th ed. (2024) — Author-Date system citation guide, chicagomanualofstyle.org.