Author-Date System in Chicago Manual of Style
The Chicago Manual of Style (CMS) offers two main citation systems: the notes-bibliography system and the author-date system. The author-date system, which is covered on this page, is widely used in the sciences and social sciences and follows a similar formatting to APA Style. This system emphasizes concise in-text citations paired with a comprehensive reference list at the end of the document. Below is an overview of the author-date system, along with examples to illustrate its application.
In-Text Citations
Basic Format
In the author-date system, in-text citations include the author’s last name and the year of publication. A page number is included when directly quoting or referring to a specific part of the text.
- General Format: (Author’s Last Name Year)
- With Page Number: (Author’s Last Name Year, Page Number)
Examples
- Paraphrasing:
- According to recent studies, climate change significantly impacts marine biodiversity (Smith 2020).
- Smith (2020) discusses the significant impacts of climate change on marine biodiversity.
- Direct Quotation:
- “Marine ecosystems are particularly vulnerable to the effects of climate change” (Smith 2020, 45).
- Smith (2020, 45) states that “marine ecosystems are particularly vulnerable to the effects of climate change.”
Reference List
Basic Format
The reference list appears at the end of the document and provides full bibliographic details for all sources cited in the text. Entries are arranged alphabetically by the author’s last name.
- General Format:
- Books: Author’s Last Name, First Name. Year. Title of Book. Place of Publication: Publisher.
- Articles: Author’s Last Name, First Name. Year. “Title of Article.” Title of Journal Volume Number (Issue Number): Page Range.
Examples
- Book:
- In-Text Citation: (Smith 2020)
- Reference List Entry: Smith, John. 2020. The Impact of Climate Change on Marine Life. New York: Marine Publishing.
- Journal Article:
- In-Text Citation: (Jones 2018)
- Reference List Entry: Jones, Emily. 2018. “Coral Reefs and Climate Adaptation.” Marine Biology Journal 35 (2): 123-140.
- Edited Book Chapter:
- In-Text Citation: (Brown 2019)
- Reference List Entry: Brown, Michael. 2019. “The Future of Coral Reefs.” In Oceans in Peril, edited by Sarah Green, 101-120. London: Oceanic Press.
- Online Source:
- In-Text Citation: (Wilson 2021)
- Reference List Entry: Wilson, David. 2021. “The Effects of Rising Sea Levels.” Climate Change Research Online. Accessed March 15, 2021. http://www.climatechangeonline.org/effects-rising-sea-levels.
Multiple Authors
Two Authors
- In-Text Citation: (Brown and Smith 2017)
- Reference List Entry: Brown, Lisa, and Mark Smith. 2017. Sustainable Marine Practices. Boston: Environmental Press.
Three or More Authors
- In-Text Citation: (Williams et al. 2016)
- Reference List Entry: Williams, Richard, Sandra Lee, and Thomas Green. 2016. “Marine Conservation Strategies.” Environmental Studies Quarterly 22 (3): 200-220.
Additional Considerations
Repeated Citations
When citing the same source multiple times, you only need to provide the full reference once in the reference list. For subsequent citations, use the same format as the first in-text citation.
Multiple Works by the Same Author
If citing multiple works by the same author from the same year, distinguish them with letters (e.g., 2020a, 2020b).
- In-Text Citation: (Smith 2020a, 2020b)
- Reference List Entry:
- Smith, John. 2020a. Marine Life under Threat. London: Oceanic Press.
- Smith, John. 2020b. “Adapting to Climate Change.” Journal of Marine Science 30 (1): 50-65.
Conclusion
The author-date system in the Chicago Manual of Style allows readers to quickly locate sources and verify information, making it particularly useful in academic and professional writing. Follow these guidelines to can ensure your work is well-documented and adheres to CMS standards.
*Content on this page was curated and edited by expert humans with the creative assistance of AI.