Chicago Author-Date (AD) is the social-sciences variant of Chicago style. Instead of footnotes, it uses parenthetical in-text citations — author name and year — paired with a Reference List at the end. If you're used to APA, you'll find Chicago AD familiar, though the formatting rules differ in important ways.
Notes-Bibliography vs. Author-Date
| Feature | Notes-Bibliography (Humanities) | Author-Date (Social Sciences) |
|---|---|---|
| In-text citation | Superscript number → footnote | (Author Year, page) |
| End list | Bibliography | Reference List (or References) |
| Subjects | History, arts, humanities | Natural, physical, social sciences |
| Page in citation | In the footnote | In parentheses: (Smith 2022, 45) |
Which one should you use? Your department or instructor will specify. When in doubt: humanities → NB; sciences and social sciences → Author-Date.
In-Text Citations
Chicago AD in-text citations follow the format: (Author Year) or (Author Year, page). Note there is no comma between author and year — this is the most common error students make when switching from APA.
- Basic: (Smith 2022)
- With page number: (Smith 2022, 45)
- Author in text: Smith (2022) argues that...
- Two authors: (Smith and Jones 2022) — use "and," not &
- Three or more: (Smith et al. 2022)
- Multiple sources: (Smith 2022; Jones 2021) — semicolons separate sources
Key difference from APA: Chicago AD does NOT use a comma between author and year: (Smith 2022), not (Smith, 2022). And it uses "and" instead of "&" in parentheses.
Reference List Formatting
Chicago AD's Reference List differs from both APA and NB style. The year comes right after the author's name, in parentheses, with a period after.
Journal Article
Omondi, James. 2022. "Digital Access and Literacy Gaps in East African Universities." Journal of African Higher Education 14 (2): 45–62. https://doi.org/10.xxxx/xxxxx.
Book
Creswell, John W. 2018. Research Design: Qualitative, Quantitative, and Mixed Methods Approaches. 5th ed. London: Sage.
Chapter in Edited Book
Bryman, Alan. 2021. "Sampling in Qualitative Research." In SAGE Handbook of Qualitative Research, edited by Paul Atkinson, Sara Delamont, Alexandru Cernat, Joseph W. Sakshaug, and Richard A. Williams, 45–62. London: Sage.
Website
World Health Organization. 2023. "Mental Health Atlas 2022." WHO. January 15, 2023. https://www.who.int/publications/i/item/9789240049338.
Key Rules
- Reference List is alphabetical by author last name, then chronological for multiple works by the same author
- Hanging indent applies (0.5 inches for second and subsequent lines)
- Article titles are in "quotation marks" (sentence case); journal names and book titles are in italics (title case)
- For journal articles, volume and issue are formatted differently from APA: 14 (2): 45–62 (no "vol." or "no.")
- Publisher location is still required for books (unlike APA 7)
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