Chicago Style Common Mistakes
Learn to identify and avoid the most frequent Chicago citation errors with clear examples and corrections.
Most Common Chicago Citation Errors
Even experienced researchers make Chicago citation mistakes. Understanding these common errors and their corrections will help you create accurate, professional citations that meet academic standards.
⚠️ Why These Mistakes Matter
- • Incorrect citations can lead to plagiarism accusations
- • Poor formatting reduces the credibility of your research
- • Inconsistent style distracts from your argument
- • Professors often deduct points for citation errors
System Confusion Errors
Mixing Notes-Bibliography and Author-Date
❌ WRONG:
The study shows significant results (Johnson 2022).¹
1. Sarah Johnson, Democratic Ideals in Practice (Chicago: University of Chicago Press, 2022), 127.
Error: Using both parenthetical citations AND footnotes
✅ CORRECT:
Notes-Bibliography:
The study shows significant results.¹
1. Sarah Johnson, Democratic Ideals in Practice (Chicago: University of Chicago Press, 2022), 127.
OR Author-Date:
The study shows significant results (Johnson 2022, 127).
Wrong Date Placement
❌ WRONG (Notes-Bibliography):
Johnson, Sarah. 2022. Democratic Ideals in Practice. Chicago: University of Chicago Press.
Error: Date after author in Notes-Bibliography system
✅ CORRECT:
Notes-Bibliography:
Johnson, Sarah. Democratic Ideals in Practice. Chicago: University of Chicago Press, 2022.
Author-Date:
Johnson, Sarah. 2022. Democratic Ideals in Practice. Chicago: University of Chicago Press.
Punctuation and Formatting Errors
Wrong Punctuation in Footnotes
❌ WRONG:
1. Sarah Johnson. Democratic Ideals in Practice. Chicago: University of Chicago Press. 2022. 127.
Error: Using periods instead of commas in footnotes
✅ CORRECT:
1. Sarah Johnson, Democratic Ideals in Practice (Chicago: University of Chicago Press, 2022), 127.
Incorrect Title Formatting
❌ WRONG:
1. David Miller, "Historical Perspectives on Democracy," "Political Science Quarterly" 85, no. 3 (Fall 2023): 245-267.
Error: Article title italicized, journal title in quotes
✅ CORRECT:
1. David Miller, "Historical Perspectives on Democracy," Political Science Quarterly 85, no. 3 (Fall 2023): 245-267.
Article titles in quotes, journal/book titles italicized
Author Name Errors
Incorrect Name Inversion
❌ WRONG (Multiple Authors):
Miller, David, and Chen, Susan. Historical Perspectives. New York: Academic Press, 2023.
Error: Both authors' names inverted
✅ CORRECT:
Miller, David, and Susan Chen. Historical Perspectives. New York: Academic Press, 2023.
Only first author's name inverted
Et Al. Usage Errors
❌ WRONG (Bibliography):
Taylor, Robert et al. Modern Research Methods. Boston: Scholarly Publications, 2022.
Error: Using "et al." in bibliography
✅ CORRECT:
Bibliography (list all authors):
Taylor, Robert, Jennifer Adams, Michael Brown, and Lisa Wilson. Modern Research Methods. Boston: Scholarly Publications, 2022.
Footnote (can use et al.):
1. Robert Taylor et al., Modern Research Methods (Boston: Scholarly Publications, 2022), 78.
Page Number and URL Errors
Missing Page Numbers
❌ WRONG:
1. Sarah Johnson, Democratic Ideals in Practice (Chicago: University of Chicago Press, 2022).
Error: No page number for specific reference
✅ CORRECT:
1. Sarah Johnson, Democratic Ideals in Practice (Chicago: University of Chicago Press, 2022), 127.
Include page number for specific references
Incorrect URL Formatting
❌ WRONG:
1. Susan Chen, "Modern Voting Patterns," American Political Association, accessed November 1, 2023, <https://www.apa.org/voting-patterns>.
Error: URLs in angle brackets
✅ CORRECT:
1. Susan Chen, "Modern Voting Patterns," American Political Association, accessed November 1, 2023, https://www.apa.org/voting-patterns.
URLs without brackets or special formatting
Access Date Misuse
Unnecessary Access Dates
❌ WRONG:
1. David Miller, "Historical Perspectives on Democracy," Political Science Quarterly 85, no. 3 (Fall 2023): 245-267, accessed November 1, 2023, https://doi.org/10.1234/psq.2023.85.3.245.
Error: Access date for stable academic source with DOI
✅ CORRECT:
1. David Miller, "Historical Perspectives on Democracy," Political Science Quarterly 85, no. 3 (Fall 2023): 245-267, https://doi.org/10.1234/psq.2023.85.3.245.
No access date needed for stable academic sources
Missing Access Dates When Needed
❌ WRONG:
1. "Breaking News: Election Results," CNN, November 5, 2023, https://cnn.com/election-results-live.
Error: No access date for time-sensitive content
✅ CORRECT:
1. "Breaking News: Election Results," CNN, November 5, 2023, accessed November 6, 2023, https://cnn.com/election-results-live.
Include access date for changing or time-sensitive content
Bibliography Organization Errors
Wrong Alphabetization
❌ WRONG:
Error: Anonymous works placed randomly
✅ CORRECT:
Anonymous works alphabetized by first significant word of title
Incorrect Hanging Indents
❌ WRONG:
University of Chicago Press, 2022.
Error: Regular indent instead of hanging indent
✅ CORRECT:
First line flush left, subsequent lines indented
How to Avoid These Mistakes
- • Choose one system: Use either Notes-Bibliography OR Author-Date consistently
- • Check punctuation rules: Footnotes use commas, bibliography uses periods
- • Format titles correctly: Articles in quotes, books/journals italicized
- • Use access dates appropriately: Only for unstable or time-sensitive content
- • Alphabetize properly: By first author's last name or first significant word
- • Apply hanging indents: In bibliography and reference list entries
- • Include page numbers: For specific references and quotations
- • Proofread carefully: Check each citation against the style guide
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