# Chicago author-date with ibid

2022, Mar 23

One of my supervisors recently suggested:

“Just a stylistic thing going forward, but where you have recently cited the same author, you can use Ibid (e.g. (Ibid: 2) or similar), rather than include their names again”

This is great advice and something I had seen before. I use Mendeley Desktop as my academic library and reference manager, which plays nicely with my writing workflow. I am used to using the so-called “Harvard” citation style, otherwise known as “author-date” because it looks like this: (Cartier-Bresson, 1999) but had not worked out how to have the software automatically detect when ibid. is appropriate.

The key to it is in the citation style or .csl file that tells your typesetting program how to format citations. There are thousands of these, publicly accessible over at the Zotero Style Repository or Github. I wanted to use a popular csl style using the globally recognised Chicago Style Manual but the use of ibid has been deprecated there. They favour the use of a short form citation which is well suited to the numbered footnote alternative to author-date.

With a little leg work I found that it is quite easy to adapt the current Chicago author-date .csl file to include the ibid feature from its numbered footnote sister.

Starting with a copy of the author-date .csl file (obviously change the name), find the <citation> tag and merge the equivalent code from the fullnote with ibid .csl file. It should look like this:

<citation et-al-min="4" et-al-use-first="1" disambiguate-add-year-suffix="true" disambiguate-add-names="true" disambiguate-add-givenname="true" givenname-disambiguation-rule="primary-name" collapse="year" after-collapse-delimiter="; ">
<layout prefix="(" suffix=")" delimiter="; ">
<group delimiter=", ">
<choose>
<if position="ibid-with-locator">
<group delimiter=", ">
<text term="ibid"/>
<text macro="point-locators-subsequent"/>
</group>
</if>
<else-if position="ibid">
<text term="ibid"/>
</else-if>
<else>
<group delimiter=", ">
<text macro="contributors-short"/>
<text macro="date-in-text"/>
<text macro="point-locators"/>
</group>
</else>
</choose>
</group>
</layout>
</citation>


It is also necessary to pull in the point-locators-subsequent macro. Paste it below the other macros in the .csl file.

## Usage

All that is required now is to point the rendering software to the style file, in my case, by editing the yaml header in my markdown document, or the _config.yml file for this site.

I don’t feel that I should push this back to the open source repositories because it’s just my own hack that works for me, but you can download my version of chicago-author-date-with-ibid.csl to adapt for your own use.

## References

1. Cartier-Bresson, Henri. 1999. The Mind’s Eye : Writings on Photography and Photographers. New York, N.Y: Aperture.