Chicago 17th edition author-date

The Chicago Manual of Style allows for two different types of reference styles. There is the Notes and Bibliography Style, and the Author-Date System (a variation of the Harvard style).  This Guide is for the Author-Date system.

In this system, sources are briefly cited in the text, usually in parentheses, by author’s last name and year of publication. Each in-text citation matches up with an entry in a reference list, where full bibliographic information is provided.

An intext reference may look like (Blanshard 2006, 151) while its reference entry may look like:

Blanshard, Alastair. 2006. Hercules: A Heroic Life. London: Granta.

Any subsequent lines in a reference are on a hanging indent.  A hanging indent is an indent that indents all text except the first line.

Most of the recommendations in the notes and bibliographies version of Chicago 17th edition are identical for the author-date system.

Unlike notes and bibliography style, each entry in the reference list must correspond to a work cited in the text.

Punctuation marks and spaces within the citation are very important. Follow the punctuation and spacing as given in the examples.

Be careful where you input information into fields in the reference types in Endnote as the same information may need to be placed in different fields for different styles.  This is particularly relevant to inputting of dates.

It is important to understand the basics of referencing and why it is important. 

A referencing style is a set of rules on how to acknowledge the thoughts, ideas and works of others in a particular way. Different types of sources eg. books, articles, each have a specific format, determined by the referencing style you are using.

Referencing is a crucial part of successful academic writing, avoiding plagiarism and maintaining academic integrity in your assignments and research.

Watch Introduction to referencing (YouTube 3m42s) to learn about the basics of referencing.

Many types of publication examples have been provided in this guide. If you cannot find the example you need, you can:

• consult The Chicago Manual of Style 17th edition.
• view the reference lists of articles in publications that use Chicago style
• consult the Instructions to authors, if writing for a journal
• type the title of the item into Library Search to see if it has a suggested citation
• adapt the rules of a similar publication type to the item
• consult other institutions’ style guides
• consult with your tutor or course coordinator.

Amongst the changes and additions some of the more important include:

In journal citations, when the date of publication includes month and day, the year may be repeated to avoid ambiguity (15.14; 15.49; 15.50 etc).

Citing author-date sources by title when no author is credited (15.39).

Citing blog posts and blogs in author-date format (15.51).

For a full list see What’s New in the 17th Edition

To print or save this guide:

1. Go to the print version of the Chicago 17th ed author date referencing style guide.
2. Click Print Page at the end of the page or use your browser's Print tool​

This guide was last updated on 22 January 2025.