Contents
Overview
The Chicago Author-Date system is the citation format specified by The Chicago Manual of Style (17th edition) for disciplines in the social sciences, natural sciences, and some areas of education and psychology. It uses parenthetical in-text citations containing the author surname and publication year, paired with a Reference list at the end of the paper.
This is the less well-known of Chicago's two systems — many students encounter "Chicago style" only through the Notes-Bibliography (NB) system used in history and humanities. If your social science or science department says "Chicago," confirm which system they mean.
Author-Date vs. Notes-Bibliography: Key Differences
In-Text
Author-Date: (Smith 2021, 45)
NB: Superscript footnote number
End Matter
Author-Date: "References" list
NB: "Bibliography"
Disciplines
Author-Date: Social/natural sciences
NB: History, arts, humanities
Look at your lecturer's handout or the journal's author guidelines. If they show parenthetical citations like (Jones 2019) in sample text, it is Author-Date. If they show superscript numbers and footnotes, it is Notes-Bibliography.
In-Text Citations
In-text citations give the author's last name, the year of publication, and (for direct quotations or specific passages) the page number. There is no comma between author and year in Chicago Author-Date — this is a common confusion with APA, which does use a comma.
| Situation | Format | Example |
|---|---|---|
| Parenthetical, paraphrase | (Author Year) | (Putnam 2000) |
| Parenthetical, specific page | (Author Year, page) | (Putnam 2000, 223) |
| Narrative citation | Author (Year) | Putnam (2000) argues… |
| Narrative with page | Author (Year, page) | Putnam (2000, 223) argues… |
| Two authors | (Author1 and Author2 Year) | (Berger and Luckmann 1966) |
| Three or more authors | (First et al. Year) | (Bourdieu et al. 1994) |
| Organisation | (Organisation Year) | (WHO 2022) |
| No author | ("Short Title" Year) | ("Digital Futures" 2021) |
Chicago Author-Date: (Putnam 2000) — no comma.
APA: (Putnam, 2000) — with comma.
Students who switch between systems frequently introduce this error.
Multiple Citations in One Parenthesis
When citing multiple sources supporting the same point, list them chronologically inside a single set of parentheses, separated by semicolons:
Reference List Rules
- Title the page References (centred, not bold in Chicago — though some institutions prefer bold).
- Entries are listed alphabetically by first author's last name.
- Use a hanging indent: first line flush left, subsequent lines indented.
- The year of publication immediately follows the author name, separated by a period — this is the key structural difference from Chicago NB's bibliography.
- Double-space throughout.
Books
Journal Articles
Chapters in Edited Books
Online and Digital Sources
Common Chicago Author-Date Errors
| Error | Correct form |
|---|---|
| Comma between author and year: (Putnam, 2000) | (Putnam 2000) — no comma in Chicago |
| Year not placed after author in reference list | Author. Year. Title… (year is 2nd element) |
| Calling it "Bibliography" instead of "References" | Author-Date uses "References"; NB uses "Bibliography" |
| Using "p." before page numbers in text | (Putnam 2000, 45) not (Putnam 2000, p. 45) |
| Italicising article titles | Article titles in quotation marks; journal name in italics |