Chicago Style, formally known as The Chicago Manual of Style (CMOS), is a widely used citation style, particularly in the humanities, social sciences, and some natural sciences. Unlike styles like APA or MLA, Chicago offers two distinct citation systems for in-text references: the Notes and Bibliography (NB) system and the Author-Date (AD) system. Understanding which system to use and how to apply it correctly is crucial for academic integrity and clarity.
This guide will break down both systems, providing practical advice and examples to help you confidently cite sources in your work.
Understanding Chicago's Two Citation Systems
The choice between the Notes and Bibliography (NB) and Author-Date (AD) systems typically depends on your academic discipline or your instructor's preference.
- Notes and Bibliography (NB) System: Primarily used in the humanities (literature, history, arts), this system employs footnotes or endnotes for in-text citations, complemented by a comprehensive bibliography at the end of the paper.
- Author-Date (AD) System: Favored in the social sciences and some natural sciences, this system uses parenthetical citations within the text, paired with a reference list (often titled "References") at the end.
Always confirm which system your institution or publication requires before you begin writing.
The Notes and Bibliography (NB) System: In-Text Citations
The NB system uses superscript numbers in your text that correspond to numbered notes (footnotes at the bottom of the page or endnotes at the end of the document). These notes provide detailed source information.
Footnotes vs. Endnotes
While the content format for footnotes and endnotes is identical, their placement differs:
- Footnotes: Appear at the bottom of the page where the reference occurs.
- Endnotes: Gathered on a separate page at the end of your document, before the bibliography.
Most word processors can automate the numbering and placement of both footnotes and endnotes, making them easier to manage.
Formatting Notes
Each time you cite a source for the first time, your note will typically include full bibliographic information. Subsequent citations of the same source can be shortened.
First Reference (Full Note)
A full note contains all the necessary publication details, similar to a bibliography entry but with slight formatting differences (e.g., commas instead of periods between elements, specific page numbers, and parentheses around publication information).
Format for a Book:
- Author's First Name Last Name, Title of Book (City: Publisher, Year), page number(s).
Example:
- Michael Pollan, The Omnivore's Dilemma: A Natural History of Four Meals (New York: Penguin Press, 2006), 99.
Format for a Journal Article:
- Author's First Name Last Name, "Title of Article," Title of Journal Volume, no. Issue (Year): page number(s), DOI or URL (if accessed online).
Example:
- Jessica L. Miller, "Redefining the American Dream: Women's Agency in Postwar Advertising," Journal of American History 105, no. 2 (2018): 405, https://doi.org/10.1093/jahist/jay169.
Format for a Website:
- Author's First Name Last Name, "Title of Page," Website Name, Last Modified Date (if available), URL.
Example:
- Sarah Zhang, "The Pandemic Could Leave Us with a Lot of Obsolete Office Buildings," The Atlantic, October 21, 2020, https://www.theatlantic.com/science/archive/2020/10/future-of-office-buildings-covid/616781/.
Subsequent References (Shortened Note)
After the first full note, subsequent citations of the same source use a shortened format, typically including only the author's last name, a shortened title (if the full title is long), and the page number(s).
Format:
- Author's Last Name, Shortened Title, page number(s).
Example (following the Pollan example above):
- Pollan, Omnivore's Dilemma, 112.
Example (following the Miller example above):
- Miller, "Redefining the American Dream," 408.
If you cite the same source consecutively, you can use "Ibid." (meaning "in the same place") to refer to the immediately preceding note. If the page number is also the same, just use "Ibid." If the page number changes, use "Ibid., page number(s)."
Example:
- Pollan, Omnivore's Dilemma, 112.
- Ibid., 115. (Refers to Pollan, Omnivore's Dilemma, page 115)
- Ibid. (Refers to Pollan, The Omnivore's Dilemma, page 115)
Placement of Note Numbers
The superscript note number should be placed at the end of the sentence or clause to which it refers, after any punctuation (periods, commas, question marks), except for a dash.
Example: "The study revealed significant shifts in consumer behavior.⁴" Example: "While some argue for strict regulations,⁵ others advocate for market-based solutions."
The Author-Date (AD) System: In-Text Citations
The AD system uses concise parenthetical citations within the text that direct readers to a corresponding entry in your reference list.
Basic Parenthetical Citation
The standard format includes the author's last name, the year of publication, and often a page number for direct quotes or specific passages.
Format: (Author Year, page number)
Example (Direct Quote): "The true measure of a society is how it treats its most vulnerable members" (Smith 2018, 45). Example (Paraphrase): Many scholars argue that societal progress should be judged by its treatment of the most vulnerable (Smith 2018).
If the author's name is mentioned in your sentence, you only need to include the year and page number in parentheses.
Example: Smith (2018, 45) argues that "the true measure of a society is how it treats its most vulnerable members."
Variations in Parenthetical Citations
Multiple Authors
- Two or Three Authors: Include all authors' last names.
(Johnson and Lee 2019, 72) (Chen, Gupta, and Rossi 2020, 115)
- Four or More Authors: Use the first author's last name followed by "et al." (Latin for "and others").
* (Davis et al. 2021, 30)
Corporate or Organizational Authors
If a source has a corporate author (e.g., a government agency, a think tank), use the organization's name.
Example: (Centers for Disease Control and Prevention 2022, 18) Shortened in subsequent citations if the name is long and clear: (CDC 2022, 20)
No Author
When no author is listed, use a shortened version of the title (usually the first few words), followed by the year. Enclose titles of articles or chapters in quotation marks and italicize titles of books or reports.
Example: ("Impact of Climate Change" 2023, 10) Example: (Global Economic Outlook 2021, 5)
No Date
If a publication date is unavailable, use "n.d." (no date).
Example: (Jones n.d., 15)
Direct Quotations
Short Quotations
Short quotations (typically fewer than 100 words or five lines of prose) are integrated into your text and enclosed in quotation marks. The parenthetical citation follows the closing quotation mark but before the final punctuation of the sentence.
Example: As one critic observed, "The novel masterfully intertwines personal narratives with historical events" (Williams 2017, 88).
Block Quotations
Longer quotations (100 words or more, or five or more lines of prose) should be set off as a block quote.
- Start a new line.
- Indent the entire block quote 0.5 inches from the left margin.
- Do not use quotation marks.
- The parenthetical citation typically appears after the final punctuation of the block quote.
Example: The author explores the complex relationship between technology and society: > Digitalization has profoundly reshaped human interaction, creating both unprecedented connectivity and new forms of isolation. The rapid evolution of social media platforms, in particular, has necessitated a reevaluation of traditional communication models and their impact on mental well-being and civic discourse. (Patel 2022, 153)
Paraphrasing and Summarizing
When you paraphrase or summarize a source, you are restating the author's ideas in your own words. While a page number is not strictly required for paraphrases in the AD system, it is highly recommended, especially when referring to a specific passage or argument, to help readers locate the information.
Example: The latest research indicates a significant rise in global temperatures over the past century (Chen 2023, 22).
Key Considerations for Both Systems
Regardless of whether you use NB or AD, several general principles apply to in-text citations in Chicago Style.
Multiple Sources in a Single Citation
If you are citing multiple sources to support a single point, separate them with semicolons within the parenthetical citation (AD) or in a single note (NB).
- AD: (Miller 2018; Johnson and Lee 2019)
- NB:
1. Miller, "Redefining the American Dream," 405; Johnson and Lee, Title of Book, 72.
Citing Indirect Sources (Sources Cited in Other Sources)
Whenever possible, find and cite the original source. If you must cite a source that you found referenced in another work (an indirect source), use "quoted in" or "cited in."
- NB:
1. John Doe, Original Work (City: Publisher, Year), 50, quoted in Jane Smith, Secondary Source (City: Publisher, Year), 120.
- AD: (Doe 1998, 50, quoted in Smith 2015, 120)
Consistency and Accuracy
The most critical aspect of citing is consistency. Ensure that all your in-text citations follow the chosen system's rules precisely and that every in-text citation has a corresponding entry in your bibliography or reference list. Inaccuracies or inconsistencies can undermine your credibility and lead to confusion for your readers. For complex projects or when you need an extra layer of assurance, remember that professional writing and editing services like those at EssayMatrix can help refine your citations and overall paper quality.
Connection to Bibliography/Reference List
Remember that in-text citations are only half of the equation. Each citation must direct your reader to a full bibliographic entry in your "Bibliography" (for NB) or "References" (for AD) section at the end of your paper. These full entries provide all the necessary details for readers to find your sources.
Why Accurate Citation Matters
Proper citation is not just an academic formality; it is a cornerstone of ethical scholarship. It acknowledges the intellectual contributions of others, allows your readers to verify your sources and explore them further, and protects you from accusations of plagiarism. Mastering Chicago Style in-text citation demonstrates your commitment to academic integrity and strengthens the credibility of your work.
By following these guidelines and paying close attention to detail, you will be well-equipped to handle Chicago Style in-text citations in your academic and professional writing.
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