The Critical Differences Between 4 Common Writing Style Guides and How to Use Them

What are writing styles?
Writing style guides or styles manuals are established sets of rules for formatting writing and citations. Writing style guides are made to make writing (including technical writing) consistent across fields of work; they also establish rules that writers follow so they don’t have to wonder ‘are YouTube videos italicized or underlined in citations’ or ‘is ‘high tech’ one hyphenated word or two’.
Why are there different writing styles?
The basic answer for why there are different writing style guides is that they originate from different organizations that had different goals and fields of study. As such, the different writing style guide put emphasis on different elements – e.g. APA and Chicago strongly focus on the year things were published while MLA focuses more on who published it.
Founded in 1883, the MLA (Modern Language Association) was established to share findings to the intellectual community, a purpose that later made it one of the most common styles used in public and private schools. The Chicago style got its start at the University of Chicago Press in 1891. The editors of the press had their own stylesheet that was so effective they published it as a manual, later a book in 1906.
In July 1892, the APA (American Psychological Association) was founded to study and discuss the, then new, field of psychology. The effects of WWII led to the field booming and the APA reorganizing and joining with other psychological groups, resulting in quadrupling the number of members from less than 1,000 in 1926 to more than 4,000 in 1945. This cemented the APA as the main organization in the field and caused their writing style to be the go-to in the field to this day.
The CSE (Council of Science Editors) got its start in 1957 as the Conference of Biology Editors to write and edit biology articles. The organization later expanded to other fields of science, being renamed in 2000 as the CSE to better represent the different fields that the organization covered.
What are the common styles, and who uses them?
The most commonly used writing style guides are MLA, APA, Chicago, and CSE. This is not even close to all writing style guides (the New York Times has its own style, for example), but they are the most commonly used writing style guides across most major industries.
MLA is mainly used in these fields:
- English
- Foreign language
- History
- Literature
- Communications
- Religions
- Other Academics (if you don’t know what style to use MLA is generally the fall back)
APA is used in these fields:
- Psychology
- Business
- Economics
- Medical/Nursing
- Engineering
- Linguistic studies
- Education

Chicago is used in these fields:
- History
- Art
- Art History
- Anthropology
- Philosophy
- Academics
CSE is used by:
- Biology
- Physics
- Chemistry
- Geology
- Medicine
- Other life sciences
MLA
This is the most commonly known of the writing style guides.
Book Citation Rules
Italicize titles of books. The edition of the book is noted after the title; first editions are not noted. A normal MLA book citation looks like this:
Author’s Last name, Author’s First Name, and Middle Name or Initial (if known). Title of Book: Subtitle of Book. Edition, Publisher, Place published, year published.
Other MLA rules include:
- Citations are listed alphabetically by the first word of the citation, usually the author’s last name.
- If no author is listed, start with the work’s title.
- The first line of citations should be indented.
- In citations, capitalize all words except for prepositions, conjunctions, and articles.
- Page numbers can be shortened to 2 digits when they are 3 or more digits long.
- When citing multiple works by the same author, use three hyphens instead of the author’s name after the first citation.
- For ebooks, replace the year published with the online publication year and add the name of the website in italics and the URL or the doi number to the end of the citation.
Web Citation Rules

Don’t include https:// in the URL in the citation. Like book titles, italicize the names of websites if they stand alone or use quotation marks if the part used is part of a larger section. When citing databases, use the permalink to stand for the URL.
A normal MLA web citation looks like this:
Author’s Last Name, First Name, Middle Name or Middle Initial (if known). “Title of Article or Section Used.” Name of Website, Name of organization’s sponsor (if known), date published or updated, URL. Date of access (required if no date is known).
MLA Formatting
All pages are double spaced. New paragraphs are left indented. The articles/document’s author is labeled in the top right corner of pages along with the page number. Dates are put in day month year format (13 June 1998) with the months in 3 letter abbreviations with the exceptions of May, June, July, and Sept, which is abbreviated to 4 letters.
Formatting of Names of Items
Italics are used for the names of: books, journals, websites, newspapers, magazines, databases, movies, works of art, plays, TV shows, radio programs, video games, scientific species names, ships, and periodicals.
Quotation marks are used for the names of: articles, essays, poems, short stories, songs, chapters of books, episodes of TV shows or radio programs, commercials, webpages, and posts.
Chicago Writing Style
Book Citation rules
A normal Chicago book citation looks like this:
Author’s Last Name, Author’s First name Middle Initial [if known]. Title of Book: Subtitle of Book (edition). (Place of Publication: Publisher, year of publication), page number(s)
For an eBook, place the URL, DOI (digital object identifier) number, or the eBook version after the page number. Place a period at the end.
Web Citation
For the last part of a journal article from a database, put with the DOI or the database name and article number or the URL. Put the name of the journal in italics with no punctuation between it and the volume of the issue. The volume and issue numbers are placed next to each other with a comma between – 11, no. 3
For Chicago style, a normal journal article from a database citation looks like this:
Author’s Last Name, Author’s First name. Middle Initial. “Title of work.” Title of Journal volume and issue numbers (year of publication): page number(s). DOI.
Lastly, a source from a website citation in Chicago style looks like this:
Author’s Last Name, Author’s First name. Middle Initial. “Title of work.” Title of site. Sponsor of Site. [date updated or date accessed in month day, year]. URL.
Page formatting
Insert a title page at the beginning of the document containing:
- the full title of the document,
- the author’s name,
- the organization (if there’s one),
- the course title (if there’s one),
- the publisher,
- the sponsor (if there is one), and
- the date.
Except the title page, number all pages in the top right corner; if desired, put your last name to the left of the page number. For tables, label each one with a number (Table 1.) and a clear title that identifies it. The label and title should be on separate lines above the table, aligned left. Give the source of the table below the table in a note in typical Chicago style.
For figures, place the label and caption below the figure, aligned left; the label and caption can be on the same line. Make sure to put all visual aids as close to the sentences that use them as possible.
APA Writing Style
Book Citation rules
APA agrees with MLA on most formatting rules. The first main difference is that the year in citations is placed in parentheses after the author’s name and before the title of the book or work rather than at the end of the citation.
Next, the second difference is that only the first word of the title and subtitle of books are capitalized; the rest of the first letters of the words are not. Lastly, the author’s first and middle initials only are included, not the first or middle name.
A normal APA book citation looks like this:
Author’s Last Name, First Initial. Middle Initial [if known]. (Year of Publication). Title of book: Subtitle of book (edition). Publisher.
For eBooks, put ‘Retrieved from [URL]’ or the DOI number at the end of the citation.
Web Citation
Put (n.d.) where the year would normally go if there is no date listed for the work. Unlike MLA, in APA:
- Only the first word of the title and subtitle of titles of works and sites are capitalized; the rest of the first letters of the words are not.
- The title is italicized, and the site name is normal formatted.
- The date of publication is placed between the author and the work’s title.
- The https//: is included in the URL.
- When the author’s name is the same as the website name, omit the site name.
A normal APA web citation looks like this:
Author’s Last Name, First Initial. Middle Initial. (Date of Publication or Update [if known]). Title of work. Site name. Retrieved [Month Day, Year,] from [URL]
Page formatting
In APA, dates (except in citations) are put in year, month, day format (1998, June 13).
CSE
Book Citation rules
CSE is like APA with a couple of differences. There is no period after the author’s first initial. The year of publication is not in parenthesis. The place of publication is placed before the publisher with a colon separating the two. If more than one city of publication is listed, use the first one or the largest or boldest. One the first letter of the first word of the title is capitalized; no part of the subtitle is capitalized.
A normal CSE book citation looks like this:

Author’s Last Name, First Initial Middle Initial. Year of Publication. Title of book: subtitle of book. edition. Place of Publication: Publisher.
For an eBook, put a semicolon after the publisher and add the [date accessed] in brackets and the URL or the doi number.
Web Citation
If the place published can’t be located on the website, use [place unknown] in its place. The author’s name is not included, only the titles of the homepage and the publisher. Either the last data the article was updated or the date that it was accessed is included in brackets after the publisher; this bracketed date is followed by the URL. A period is placed at the end of the URL.
A normal CSE web citation looks like this:
Title of Homepage. Date of publication. Edition. Place of publication: Publisher; [date updated or date accessed]. URL.
CSE formatting
Citations in CSE are single spaced, but the first line of a citation is still indented like MLA. Months are abbreviated to 3 letters with no period, and dates are written in year month day format (1998 June 13). Don’t use underlining, italics, or bold for the names of books, sites, shows, journals, albums, etc.