Nathan D.
Nathan D.

Chicago Style Author Date System - All You Need to Know

8 min read

Published on: May 10, 2024

Last updated on: May 11, 2024

Chicago Style Author-Date Format

In academic writing, referencing sources accurately is important for credibility and integrity.

The Author-Date system in the Chicago style offers a structured approach to citing sources within the text and compiling a reference list. It's widely used across disciplines, from humanities to social sciences.

In this guide, we'll break down the Chicago Style Author-Date system into simple steps, helping you understand how to incorporate in-text citations and create a reference list.

In-Text Citations in Chicago Style Author-Date

In Chicago Style Author-Date, in-text citations are placed within parentheses at the end of a sentence or clause. They include the author's last name and the year of publication without any punctuation in between.

For instance, below is an in-text Chicago author-date citation example:

The discovery was groundbreaking (Chris 2010).

If directly quoting, you should add a page number after a comma. 

Here’s an example:

The study “found significant results” (Lewis 2015, 42).

If you’re referring to a page range in the citation, separate the pages by an en dash.

(Lewis 2015, 42-43)

Multiple citations are always separated by semicolons:

Recent studies on climate change have provided compelling evidence (Brown 2008; Phillips 2012), suggesting a need for urgent global action.

When the author's name is already introduced in the text, the citation should follow immediately and include only the publication date. If quoting directly, incorporate the page number right after the quoted text.

In his analysis, Rodriguez (2022) emphasizes the role of artificial intelligence in “customizing learning experiences for individual students” (42).

In-Text Citation: Multiple Authors

In Chicago author-date style, in-text citations for multiple authors follow a specific format. 

Let's say you have a source written by three authors: Hernandez, Russel, and Rory, and you want to cite it in your text.

The basic format for in-text citations with multiple authors is:

  • List all the authors the first time you cite the source, followed by the publication year in parentheses. 
  • For subsequent citations of the same source, you can use the first author's last name followed by “et al.” and the publication year.

Here's how it would look:

First citation:

(Hernandez, Russel, and Rory 2010)

Subsequent citations:

(Hernandez et al. 2010)

Chicago Style Author-Date References Page

According to the Chicago Manual of Style, each citation corresponds to a reference list entry that comes at the end of the paper. The reference list page can either be titled “References” or “Works Cited” page. 

Here are the standard formatting guidelines for a Chicago author-date style reference page.

  • Bold the title of the reference page
  • Each entry begins with the author's last name followed by the publication year
  • All reference list entries are alphabetized by the author’s last name
  • Use single-spacing throughout the page, but use a blank line between every reference to increase readability
  • References are formatted with a hanging indent, where the first line of each entry is flush left, and subsequent lines are indented.
  • Provide detailed information for each source, including the title, publication date, and other relevant details. We will discuss the details in the examples section. 

Here is an example of a reference list entry in the Chicago style. 

García Márquez, Gabriel. 1985. One Hundred Years of Solitude. Translated by Gregory Rabassa. New York: Harper & Row.


Chicago Style Author-Date System: Reference List Format

When you’re adding references in your Chicago style paper, you need to follow certain guidelines for different types of sources. Read on to learn the format for multiple source types along with Chicago citation style examples.

Citation for a Book

Adams, Emily. 2017. Beyond the Horizon. New York: HarperCollins.

This entry follows the Chicago Style Author-Date system, including the author's name, publication year, book title, place of publication, and publisher.

For Chapter of a Book

Johnson, Mark. 2019. “Exploring Cultural Diversity.” In Cultural Perspectives, edited by Emily Chen, 45-62. Chicago: University of Chicago Press.

This entry includes the chapter author's name, publication year, chapter title, book title, editor's name, page range, place of publication, and publisher.

For E-Book

Smith, Michael. 2020. Digital Revolution. E-book. Boston: Beacon Press.

The entry for an e-book includes the same elements as a standard book entry, with the addition of specifying the format as “E-book.”

For Book with Multiple Authors

Brown, Lisa, and John Miller. 2018. The Power of Collaboration. New York: Random House.

When there are multiple authors, list their names in the same order as they appear on the title page, separated by commas.

For Multiple Books By the Same Author

Lee, Sarah. 2015a. Exploring the Unknown. Boston: Beacon Press.

Lee, Sarah. 2015b. Adventures in Wonderland. New York: HarperCollins.

When citing multiple works by the same author published in the same year, differentiate them with letters (e.g., 2015a, 2015b).

For Journal Article

Patel, Rahul. 2019. “Exploring Quantum Realms.” Physics Review 25, no. 3: 112-128. DOI:10.1234/pr.2019.0123456.

Journal article entries include the author's name, publication year, article title, journal name, volume and issue number, page range, and Digital Object Identifier (DOI) or URL.

For Website

Anderson, Sarah. 2021. “Unraveling the Mysteries of Deep Space.” Cosmos Discovery. Accessed January 10, 2022.  https://www.cosmosdiscovery.com/unraveling-deep-space-mysteries.

This example follows the Chicago Style Author-Date system for a website entry. It includes the author's name, publication year, page title in quotation marks, website or web page name in italics, access or revision date, and URL. 

For Newspaper or Magazine Article

Smith, Emma. 2020. “The Power of Art.” Artistic Insights, February 12, 2020, 4-5.

Newspaper or magazine article entries include the author's name, publication year, article title, newspaper or magazine name, publication date, and page numbers.

For Thesis or Dissertation

Johnson, Robert. 2018. “Exploring Cultural Dynamics.” PhD diss., University of Chicago, Chicago, IL.

Thesis or dissertation entries include the author's name, publication year, title, degree type, institution name, and location.

For Sources With Missing Information

When citing references with missing information, such as the author's name, in the Chicago Style Author-Date system, you typically employ different approaches based on the type of source. 

Here are some instances and how to handle them:

Anonymous Authorship:

If a source is explicitly attributed to “Anonymous,” you can use “Anonymous” as the author's name in the reference entry.

Anonymous. 2021. Unknown Wonders. E-book. New York: Random House.

Unknown Author:

If the author's name is not provided or is unknown, you can use the title of the source as the first element of the reference entry. This helps in alphabetizing the entry in the reference list.

The Mystery of the Lost City. 2019. E-book. London: Penguin Books.

Organization as Author:

If a source is issued by an organization without a specific author listed (e.g., a press release or pamphlet), you can list the organization as the author in the reference entry.

National Geographic Society. 2017. Wildlife Conservation Efforts. Washington, D.C.: National Geographic.

Missing Publication Date:

If a publication date is not available, you can use “n.d.” (no date) in place of the date in the reference entry.

Smith, John. Exploring the Universe. E-book. New York: HarperCollins, n.d.

Missing Location or Publisher:

If the place of publication or publisher is not provided, you can omit this information from the reference entry.

Green, Emily. 2018. Sustainable Living Practices. E-book. n.p.: Green Press.

In each case, the reference entries follow the Chicago Style Author-Date system and adapt to the specific scenario where information is missing or unavailable. These examples demonstrate how to handle various instances of citing references with missing information while maintaining consistency and accuracy in your reference list.

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Frequently Asked Questions

Which Citation format should I choose between Chicago Style Author Date vs. Notes-Bibliography?

Chicago Style Author-Date is often preferred in disciplines like the sciences and social sciences, where concise and easily accessible citations are prioritized. Notes-Bibliography is commonly used in the humanities, where additional contextual information or explanatory notes are necessary for understanding the sources cited.

What is the difference between Chicago Style Author-Date and Notes-Bibliography?

Chicago Style Author-Date utilizes parenthetical in-text citations with the author's last name and publication year, followed by a corresponding reference list. Notes-Bibliography, on the other hand, uses footnotes or endnotes for citations within the text, along with a bibliography at the end of the document. The choice between the two styles often depends on the preferences of the academic discipline or publisher.

How do I format Chicago Style footnotes?

In Chicago Style, footnotes are typically used for citation purposes. They appear at the bottom of the page where the citation is referenced and include the author's name, title of the work, publication information, and page number if applicable. The format may vary slightly depending on the type of source.

Nathan D.

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Nathan D. (Educational Theories)

Introducing Nathan D., PhD, an esteemed author on PerfectEssayWriter.ai. With a profound background in Literary Analysis and expertise in Educational Theories, Nathan brings a wealth of knowledge and insight to his writings. His passion for dissecting literature and exploring educational concepts shines through in his meticulously crafted essays and analyses. As a seasoned academic, Nathan's contributions enrich our platform, offering valuable perspectives and engaging content for our readers.

Introducing Nathan D., PhD, an esteemed author on PerfectEssayWriter.ai. With a profound background in Literary Analysis and expertise in Educational Theories, Nathan brings a wealth of knowledge and insight to his writings. His passion for dissecting literature and exploring educational concepts shines through in his meticulously crafted essays and analyses. As a seasoned academic, Nathan's contributions enrich our platform, offering valuable perspectives and engaging content for our readers.

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