How to Use Chicago Style: Author-Date System (17th Ed.)

Your professor told you to use “Chicago style,” but your classmates are using footnotes. Your prompt, however, asks for parenthetical citations like (Smith 2020).

You’ve discovered the *other* Chicago: the Author-Date system. While the Notes-Bibliography (NB) system is famous in history, the Author-Date system is preferred in the social sciences (like economics, sociology, and business) for its efficiency.

This guide is the foundational resource for the Chicago 17th edition Author-Date system. We will cover the “macro” context (how it’s different from NB and APA) and the “micro” skills (how to format your in-text citations and “References” list).

What is the Chicago Author-Date System?

Chicago Author-Date is one of two systems in *The Chicago Manual of Style*. It is a citation style that uses parenthetical in-text citations to direct the reader to a full entry in a “References” list at the end of the paper.

Author-Date vs. Notes-Bibliography (The Key Difference)

This is the most important distinction. Both are “Chicago Style.”

Chicago Author-Date vs. APA

The Chicago Author-Date system looks very similar to APA style, but has key differences in punctuation of in-text citations and the format of the reference list.

• Chicago (Author-Date): (Smith 2020, 15). The reference list entry begins: `Smith, John. 2020.`
• APA: (Smith, 2020, p. 15). The reference list entry begins: `Smith, J. (2020).`

General Paper Formatting (Author-Date)

Paper formatting is identical to the Notes-Bibliography system. As the official manual notes, the core page setup is consistent.

• Margins: 1-inch margins on all sides.
• Font: A readable, standard font. Times New Roman 12pt is standard.
• Spacing: The main body of your paper must be double-spaced.
• Page Numbers: Page numbers begin on the first page of *text* (not the title page). They go in the top-right header.
• Title Page: Chicago style requires a separate title page. Center your title one-third down, and your name/course/date two-thirds down.

Chicago In-Text Citations (Author-Date)

This is the core of the Author-Date system. It’s how you cite sources in your text.

The Basic Rule: (Author Date, Page)

The standard citation includes the author’s last name, the year of publication, and *if needed*, a page number.

• No comma is used between the author and the date.
• A comma is used before the page number.
• “p.” or “pp.” are not used for page numbers.

Parenthetical vs. Narrative Citations

You have two ways to integrate this citation:

• Parenthetical: The full citation is placed at the end of the sentence in parentheses.

  Example: Recent research on social mobility confirms this trend (Smith 2020, 15-17).

• Narrative: The author’s name is used in the sentence, and the year (and page) are placed in parentheses.

  Example: Smith (2020, 15-17) confirms this trend in his research on social mobility.

When to use page numbers? Use a page number when you use a direct quote, paraphrase a specific passage, or want to point the reader to a specific piece of data.

Citing by Number of Authors

This is a major difference from APA.

• 1-3 Authors: List all authors’ last names.

  Example (1): (Smith 2020, 15)

  Example (2): (Smith and Jones 2021, 10)

  Example (3): (Smith, Jones, and Davis 2022, 5)

• 4 or More Authors: Use the first author’s last name followed by “et al.”

  Example: (Smith et al. 2023, 22)

How to Cite Block Quotes

For quotes of 100 words or more (or five or more lines of text), use a block quote.

• Start the quote on a new line.
• Indent the entire block 0.5 inches.
• Do not use quotation marks.
• The parenthetical (Author Date, Page) citation comes *after* the period.

How to Format the “References” List

The “References” page is your alphabetical list of all sources. It has very specific formatting rules.

Core Formatting Rules

1. New Page: Start on a new page after your main text.
2. Title: Center the title “References” at the top (not bold).
3. Alphabetical: Alphabetize all entries by the author’s last name.
4. Hanging Indent: Use a 0.5-inch hanging indent.
5. Spacing: Entries are single-spaced, with a blank line *between* them.

In-Text Citation vs. Reference List Entry

The reference list format differs from both footnotes and APA references. The year moves directly after the author’s name.

Note the key differences: Punctuation in the in-text citation, and the placement of the year in the reference list.

Common Chicago (Author-Date) Reference Examples

Here are formats for common sources. For more, see the official Chicago (Author-Date) guide.

Book with One Author

Journal Article (with DOI)

Webpage

Note on Access Dates: Chicago requires a “last modified” date if available. If not, use an access date (“Accessed November 14, 2025,”).

How to Handle Missing Information

No Author

Move the title to the author position. Use the first few words of the title in your in-text citation.

In-Text: (*Merriam-Webster’s* 2003, 12)

No Date

Use the abbreviation “n.d.” (for “no date”) in place of the year.

In-Text: (Smith n.d.)