Organizations that publish detailed, research-based, or long-form documents often rely on The Chicago Manual of Style to create consistent, professional content. Chicago Style is widely used in publishing, academic writing, research, and professional documents that require careful attention to grammar, formatting, citations, and structure.
For organizations producing reports, publications, white papers, research materials, and other detailed documents, following Chicago Style helps ensure information is presented clearly and consistently.
However, Chicago Style includes detailed rules, and even experienced writers can make mistakes.
Small inconsistencies in punctuation, citations, capitalization, and formatting can affect the professionalism of a document.
Understanding common Chicago Style mistakes can help organizations create stronger, more polished publications.
Inconsistent Use of the Serial Comma
One of the most recognizable Chicago Style rules is the use of the serial comma, also known as the Oxford comma.
Unlike AP Style, Chicago Style generally uses a comma before the final item in a list.
Chicago Style example:
The organization supports students, families, and educators.
A common mistake is leaving out the final comma.
Incorrect:
The organization supports students, families and educators.
The serial comma improves clarity, especially in complex sentences where readers may misunderstand how items relate to one another.
Incorrect Formatting of Titles
Chicago Style provides specific guidance for formatting titles of books, articles, reports, journals, and other works.
Generally:
- Titles of larger works are italicized.
- Titles of shorter works appear in quotation marks.
Examples:
Book title:
The Chicago Manual of Style
Article title:
“Writing Clearly for Public Audiences”
A common mistake is using the same formatting for every type of title.
Confusing Notes and Bibliography With Author-Date Citations
Chicago Style supports two citation systems:
- Notes and bibliography
- Author-date
Choosing the wrong system or mixing the two can create inconsistencies.
The notes and bibliography system is commonly used in:
- Humanities
- Publishing
- History
- Literature
The author-date system is often used in:
- Social sciences
- Sciences
- Research-focused writing
Organizations should choose the appropriate system based on their document type and audience.
Incorrect Footnote and Endnote Formatting
When using Chicago’s notes and bibliography system, citations require careful formatting.
Common mistakes include:
- Missing publication information
- Incorrect punctuation
- Inconsistent author names
- Improper page references
- Incorrect order of information
Footnotes and endnotes should follow the same format throughout the document.
Incorrect Use of Numbers
Chicago Style has specific rules for writing numbers.
Generally, Chicago Style spells out numbers from zero through one hundred in formal writing, although exceptions apply.
Example:
The organization surveyed twenty-five participants.
However, numerals are often used for:
- Measurements
- Percentages
- Dates
- Addresses
- Large numbers
- Technical information
Because number rules depend on context, careful editing is important.
Inconsistent Treatment of Percentages
Chicago Style allows flexibility when writing percentages, but organizations should choose a consistent approach.
For example, a document may use:
25 percent
or
25%
depending on the publication’s preferences and context.
A common mistake is switching between formats throughout the same document.
Consistency is more important than choosing one format over another.
Incorrect Capitalization in Titles and Headings
Chicago Style uses title case for many headings and titles.
This means major words are capitalized, while certain shorter words are lowercase unless they begin or end the title.
Example:
Improving Communication Across Diverse Audiences
Common mistakes include:
- Capitalizing every word
- Lowercasing important words
- Using inconsistent capitalization across headings
Consistent headings improve readability and professionalism.
Misusing “That” and “Which”
Chicago Style follows traditional grammar rules for restrictive and nonrestrictive clauses.
Use that for essential information.
The reports that include financial data require approval.
Use which for additional information.
The reports, which were published in June, include financial data.
Using these words correctly helps readers understand which information is necessary and which is additional.
Incorrect Use of Hyphens
Chicago Style provides detailed guidance on compound words and modifiers.
Use a hyphen when two or more words work together to describe a noun.
Correct:
A five-year plan
Incorrect:
A five year plan
However, hyphen rules depend on how words are used in a sentence.
A professional editor can help ensure consistent treatment of compound terms.
Overusing or Misusing Italics
Chicago Style uses italics for specific purposes, including:
- Titles of major works
- Foreign words in some contexts
- Emphasis in limited situations
A common mistake is using italics too frequently.
Overusing emphasis can make documents appear inconsistent and distract readers from important information.
Incorrect Treatment of Abbreviations
Chicago Style generally recommends limiting unnecessary abbreviations, especially when writing for broad audiences.
Common mistakes include:
- Introducing abbreviations without explanation
- Using too many shortened terms
- Inconsistently abbreviating the same word
Organizations should consider whether an abbreviation helps or hinders reader understanding.
Inconsistent Use of Capitalization
Chicago Style places importance on consistent capitalization.
Common areas where mistakes occur include:
- Department names
- Program names
- Titles
- Organizations
- Academic subjects
- Government terms
For example, an organization should decide whether a program name is a formal title and apply that decision consistently throughout the document.
Incorrect Reference Formatting
Chicago Style bibliographies require careful attention to detail.
Common mistakes include:
- Missing information
- Incorrect punctuation
- Incorrect ordering
- Inconsistent formatting
- Missing publication details
Accurate references help readers locate sources and strengthen the credibility of the document.
Ignoring the Organization’s Internal Style Guide
Many organizations use Chicago Style as a foundation while creating additional internal rules.
An internal style guide may address:
- Preferred terminology
- Brand voice
- Program names
- Formatting preferences
- Organizational language
A common mistake is following Chicago Style while ignoring an organization’s established communication standards.
Related: Which Style Guide Does Your Organization Need?
Why Chicago Style Consistency Matters
Chicago Style is often used for documents that require accuracy, credibility, and attention to detail. Inconsistent formatting or citation errors can distract readers and weaken the impact of important information.
Following Chicago Style helps organizations:
- Improve readability
- Present information professionally
- Maintain consistency
- Strengthen credibility
- Create polished publications
A consistent editorial approach allows readers to focus on the content rather than formatting issues.
Related: AP Style vs. Chicago Style
How Professional Editing Helps
Chicago Style includes detailed rules that can be difficult to apply consistently, especially in long documents with multiple contributors.
Professional editors help organizations maintain Chicago Style standards while preserving their unique voice and communication goals.
An editor can review:
- Citations
- References
- Grammar
- Punctuation
- Formatting
- Headings
- Numbers
- Capitalization
- Style consistency
Professional editing helps ensure your document meets professional standards before publication.
At SP Editing, we provide professional editing and proofreading services for nonprofits, government agencies, educational institutions, healthcare organizations, foundations, and businesses.
We help organizations prepare polished documents, including:
- Annual reports
- Research publications
- Grant proposals
- White papers
- Policy documents
- Educational materials
- Long-form reports
Our editors help ensure documents are clear, consistent, and aligned with the appropriate style standards.
Whether your organization uses Chicago Style for research, publishing, or professional communications, SP Editing can help you create accurate, polished documents that communicate your information clearly and confidently.
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