Chicago Notes-Bibliography vs Author-Date: Which to Use

The Chicago Manual of Style (17th edition) offers two distinct citation systems: Notes-Bibliography (NB) and Author-Date (AD). Both are valid Chicago style — the difference lies in how sources are cited within the text and listed at the end of the paper.

Notes-Bibliography uses footnotes or endnotes (superscript numbers in the text) paired with a bibliography page. Author-Date uses parenthetical citations (author last name and year) paired with a reference list. Your choice depends on your academic discipline and instructor preferences.

Notes-Bibliography is the preferred system in the humanities: history, literature, philosophy, arts, and theology. It allows for discursive footnotes — you can add commentary, additional references, or clarifications without interrupting the flow of your argument.

In the NB system, the first citation of a source uses a full note (all publication details), while subsequent citations use a shortened form with the author's last name, a brief title, and a page number. The bibliography at the end lists all sources alphabetically by author.

Author-Date is standard in the sciences and social sciences: psychology, sociology, economics, and natural sciences. It is concise and familiar to readers accustomed to APA-style parenthetical references.

In-text citations include the author's last name and year of publication, optionally with a page number: (Smith 2023, 45). The reference list at the end is organized alphabetically and includes full publication details with the year placed immediately after the author name.

The main differences are: (1) NB uses footnotes while AD uses parenthetical citations; (2) NB has a "bibliography" while AD has a "reference list"; (3) NB supports discursive notes while AD is purely referential; (4) NB lists the author's full name (first last) in notes but inverts it (last, first) in the bibliography, while AD always inverts.

Both systems share the same core Chicago rules for formatting titles, publisher names, dates, and URLs. The difference is presentation, not substance. CiteMe supports both Chicago Notes-Bibliography and Author-Date formatting — select your preferred variant in the style picker.