American Psychological Association (APA) Style

What Is APA Style?

APA style  is a set of guidelines for writing in psychology and related fields. These guidelines are set down in the Publication Manual of the American Psychological Association (APA, 2020)^[1]. The Publication Manual originated in 1929 as a short journal article that provided basic standards for preparing manuscripts to be submitted for publication (Bentley et al., 1929)^[2]. It was later expanded and published as a book by the association and is now in its seventh edition. The primary purpose of APA style is to facilitate scientific communication by promoting clarity of expression and by standardizing the organization and content of research articles and book chapters. It is easier to write about research when you know what information to present, the order in which to present it, and even the style in which to present it. Likewise, it is easier to read about research when it is presented in familiar and expected ways.

APA style is best thought of as a “genre” of writing that is appropriate for presenting the results of psychological research—especially in academic and professional contexts. It is not synonymous with “good writing” in general. You would not write a literary analysis for an English class, even if it were based on psychoanalytic concepts, in APA style. You would write it in Modern Language Association (MLA) style instead. And you would not write a newspaper article, even if it were about a new breakthrough in behavioral neuroscience, in APA style. You would write it in Associated Press (AP) style instead. At the same time, you would not write an empirical research report in MLA style, in AP style, or in the style of a romance novel, an email to a friend, or a shopping list. You would write it in APA style. Part of being a good writer in general is adopting a style that is appropriate to the writing task at hand, and for writing about psychological research, this is APA style.

The Levels of APA Style

Because APA style consists of a large number and variety of guidelines—the Publication Manual is more than 400 pages long—it can be useful to think about it in terms of three basic levels. The first is the overall organization of an article (which is covered in Chapter 2 “Paper Elements and Format” and Chapter 3 "Journal Article Reporting Standards" of the Publication Manual). Empirical research reports, in particular, have several distinct sections that always appear in the same order:

• Title page. Presents the article title and author names and affiliations.
• Abstract. Summarizes the research.
• Introduction. Describes previous research and the rationale for the current study.
• Method. Describes how the study was conducted.
• Results. Describes the results of the study.
• Discussion. Summarizes the study and discusses its implications.
• References. Lists the references cited throughout the article.

The second level of APA style can be referred to as  high-level style  (covered in Chapter 4 “Writing Style and Grammar” of the Publication Manual), which includes guidelines for the clear expression of ideas. There are two important themes here. One is that APA-style writing is formal rather than informal. It adopts a tone that is appropriate for communicating with professional colleagues—other researchers and practitioners—who share an interest in the topic. Beyond this shared interest, however, these colleagues are not necessarily similar to the writer or to each other. A graduate student in British Columbia might be writing an article that will be read by a young psychotherapist in Toronto and a respected professor of psychology in Tokyo. Thus formal writing avoids slang, contractions, pop culture references, humor, and other elements that would be acceptable in talking with a friend or in writing informally.

The second theme of high-level APA style is that it is straightforward. This means that it communicates ideas as simply and clearly as possible, putting the focus on the ideas themselves and not on how they are communicated. Thus APA-style writing minimizes literary devices such as metaphor, imagery, irony, suspense, and so on. Again, humor is kept to a minimum. Sentences are short and direct. Technical terms must be used, but they are used to improve communication, not simply to make the writing sound more “scientific.” For example, if participants immersed their hands in a bucket of ice water, it is better just to write this than to write that they “were subjected to a pain-inducement apparatus.” At the same time, however, there is no better way to communicate that a between-subjects design was used than to use the term “between-subjects design.”

Another important element of high-level APA style is the avoidance of language that is biased against particular groups. This is not only to avoid offending people—why would you want to offend people who are interested in your work?—but also for the sake of scientific objectivity and accuracy. For example, the term sexual orientation should be used instead of sexual preference because people do not generally experience their orientation as a “preference,” nor is it as easily changeable as this term suggests. Specific guidance about using bias-free language originated with the APA Committee on Lesbian, Gay, and Bisexual Concerns Joint Task Force on Guidelines for Psychotherapy with Lesbian, Gay, and Bisexual Clients (2000)^[4]and is now included Chapter 5 "Bias-Free Language Guidelines".

The general principles for avoiding biased language are fairly simple. First, be sensitive to labels by avoiding terms that are offensive or have negative connotations. This includes avoiding terms that identify people with a disorder or other problem they happen to have. Instead, refer to the individual, what the APA Publication Manual refers to as putting the “person first.” For example, people diagnosed with schizophrenia is better than schizophrenics. Second, use more specific terms rather than more general ones. For example, Chinese Americans is better than Asian Americans if everyone in the group is, in fact, Chinese American. Third, avoid objectifying research participants. Instead, acknowledge their active contribution to the research. For example, “The students completed the questionnaire” is better than “The subjects were administered the questionnaire.” Note that this principle also makes for clearer, more engaging writing. Table 11.1 shows several more examples that follow these general principles.

Keep in mind, however, that some individuals might prefer "identity-first" language such as "blind person" or "autistic person" for personal reasons, often related to a sense of pride. Chapter 5 of the Publication Manual provides specific guidance for choosing between person-first and identity-first language, noting that either is acceptable and a mix of the two might be appropriate. Most importantly, seeking perspectives from members of that community and matching the language they use to describe themselves would be advantageous as well as ethical.

A previous edition of the Publication Manual strongly discouraged the use of the term subjects (except for nonhumans) and strongly encouraged the use of participants instead. The current edition, however, acknowledges that subjects can still be appropriate in general use and when referring to statistical concepts and research designs (e.g., "between-subjects design"). But it also encourages the use of more specific terms when possible: university students, children, respondents, and so on.

The third level of APA style can be referred to as  low-level style  (which is covered in Chapter 6 “Mechanics of Style” through Chapter 10 “Reference Examples” of the Publication Manual). Low-level style includes all the specific guidelines pertaining to spelling, grammar, references and in-text citations, numbers and statistics, figures and tables, and so on. There are so many low-level guidelines that even experienced professionals need to consult the Publication Manual from time to time. Table 11.2 contains some of the most common types of APA style errors based on an analysis of manuscripts submitted to one professional journal over a 6-year period (Onwuegbuzie et al., 2010)^[5]. These errors were committed by professional researchers but are probably similar to those that students commit the most too. See also Note 11.8 “Online APA Style Resources” in this section and, of course, the Publication Manual itself.

APA-Style References and Citations

Because science is a large-scale collaboration among researchers, references to the work of other researchers are extremely important. Their importance is reflected in the extensive and detailed set of rules for formatting and using them.

References

At the end of an APA-style article or book chapter is a list that contains references  to all the works cited in the text (and only the works cited in the text). The reference list begins on its own page, with the heading “References,” centered in upper and lower case. The references themselves are then listed alphabetically according to the last names of the first named author for each citation. (As in the rest of an APA-style manuscript, everything is double-spaced.) Many different kinds of works might be cited in APA-style articles and book chapters, including magazine articles, websites, government documents, and even television shows. Of course, you should consult the Publication Manual or Online APA Style Resources for details on how to format them. Here we will focus on formatting references for the three most common kinds of works cited in APA style: journal articles, books, and book chapters.

Journal Articles

For journal articles, the generic format for a reference is as follows:

Author, A. A., Author, B. B., & Author, C. C. (year). Title of article. Title of Journal, volume(issue), pp–pp. https://doi.org/xx.xxx/xxxxxxx

Here is a concrete example:

Adair, J. G., & Vohra, N. (2003). The explosion of knowledge, references, and citations: Psychology’s unique response to a crisis. American Psychologist, 58(1), 15–23. https://doi.org/10.1037/0003-066X.58.1.15

There are several things to notice here. The reference includes a hanging indent. That is, the first line of the reference is not indented but all subsequent lines are. The authors’ names appear in the same order as on the article, which reflects the authors’ relative contributions to the research. Only the authors’ last names and initials appear, and the names are separated by commas with an ampersand (&) between the last two. This is true even when there are only two authors. Only the first word of the article title is capitalized. The only exceptions are for words that are proper nouns or adjectives (e.g., “Freudian”) or if there is a subtitle, in which case the first word of the subtitle is also capitalized. In the journal title, however, all the important words are capitalized. The journal title and volume number are italicized; however, the issue number (listed within parentheses) is not.

At the very end of the reference is the URL (web address) that contains the digital object identifier (DOI); this URL provides a permanent link to the location of the article online, usually via the publisher's website. Note that for articles that aren't Open Access, only the abstract or summary will be available; check with your librarian if you need help locating the full text of any source.

Include the URL with DOI if it is available. It can generally be found on the journal's website and is often displayed on the first page of the published article. If you can't locate the URL with DOI, but you know the DOI itself, simply add https://doi.org/ prior to the DOI number to construct the URL; make sure you don't include spaces and that you test the URL you created to ensure it works. Another option is to search for the article using the Crossref metadata search (https://search.crossref.org/) to find the URL with DOI. Not all articles have a DOI, especially articles published before widespread internet usage in the early 2000s. Some newer articles don't have DOIs because the publisher does not assign them; this is less common in psychology compared with fields such as education and the arts/humanities.

Books

For a book, the generic format and a concrete example are as follows:

Author, A. A. (year). Title of book. Publisher.

Kashdan, T., & Biswas-Diener, R. (2014). The upside of your dark side. Hudson Street Press.

Book Chapters

For a chapter in an edited book, the generic format and a concrete example are as follows:

Author, A. A., Author, B. B., & Author, C. C. (year). Title of chapter. In A. A. Editor, B. B. Editor, & C. C. Editor (Eds.), Title of book (pp. xxx–xxx). Publisher.

Lilienfeld, S. O., & Lynn, S. J. (2003). Dissociative identity disorder: Multiple personalities, multiple controversies. In S. O. Lilienfeld, S. J. Lynn, & J. M. Lohr (Eds.), Science and pseudoscience in clinical psychology (pp. 109–142). Guilford Press.

Notice that references for books and book chapters are similar to those for journal articles, but there are several differences too. For an edited book, the names of the editors appear with their first and middle initials followed by their last names (not the other way around)—with the abbreviation “Eds.” (or “Ed.,” if there is only one) appearing in parentheses immediately after the final editor’s name. Only the first word of a book title is capitalized (with the exceptions noted for article titles), and the entire title is italicized. For a chapter in an edited book, the page numbers of the chapter appear in parentheses after the book title with the abbreviation “pp.” Finally, both formats end with publisher; note that the publisher's location is not required in the current edition of the Publication Manual.

In-text Citations

When you refer to another researcher’s idea, you must include an in-text citation to the work in which that idea originally appeared and a full reference to that work in the reference list. What counts as an idea that must be cited? In general, this includes phenomena discovered by other researchers, theories they have developed, hypotheses they have derived, and specific methods they have used (e.g., specific questionnaires or stimulus materials). Citations should also appear for factual information that is not common knowledge so that other researchers can check that information for themselves. For example, in an article on the effect of cell phone usage on driving ability, the writer might cite official statistics on the number of cell phone–related accidents that occur each year. Among the ideas that do not need citations are widely shared methodological and statistical concepts (e.g., between-subjects design, t test) and statements that are so broad that they would be difficult for anyone to argue with (e.g., “Working memory plays a role in many daily activities.”). Be careful, though, because “common knowledge” about human behavior is often incorrect. Therefore, when in doubt, find an appropriate reference to cite or remove the questionable assertion.

When you cite a work in the text of your manuscript, there are two ways to do it. Both include only the last names of the authors and the year of publication. The first method is called a narrative citation: use the authors’ last names in the sentence (with no first names or initials) followed immediately by the year of publication in parentheses. Here are some examples:

Burger (2008) conducted a replication of Milgram’s (1963) original obedience study.

Although many people believe that squirrels are noisier than chipmunks, Gruber and Harton (2025) found essentially no difference in the number of vocalizations by the two species.

Notice several things. First, the authors’ names are treated grammatically as names of people, not as things. It is better to write “a replication of Milgram’s (1963) study” than “a replication of Milgram (1963)”. Second, when there are two authors, the names are not separated by commas, but when there are three or more authors, they are. Third, the word and (rather than an ampersand) is used to join the authors’ names. Fourth, the year follows immediately after the final author’s name. An additional point, which is not illustrated in these examples but is illustrated in Figure 8.3 in the Publication Manual, is that the year only needs to be included the first time a particular work is cited in the same paragraph.

The second way to cite an article or a book chapter is in a parenthetical citation, which consists of including the authors’ last names and the year of publication in parentheses following the idea that is being credited. Here are some examples:

People can be surprisingly obedient to authority figures (Burger, 2008; Milgram, 1963).

Recent evidence suggests that men and women are similarly talkative (Mehl et al., 2007). (See below for information about when "et al." is used in in-text citations.)

One thing to notice about such parenthetical citations is that they are often placed at the end of the sentence, which minimizes their disruption to the flow of that sentence. In contrast to the narrative citation method, the parenthetical method always includes the year—even when the citation is given multiple times in the same paragraph. Notice also that when there are multiple citations in the same set of parentheses, they are organized alphabetically by the name of the first author and separated by semicolons.

There are no strict rules for deciding which of the two citation styles to use. Most articles and book chapters contain a mixture of the two. In general, however, the first approach works well when you want to emphasize the person who conducted the research—for example, if you were comparing the theories of two prominent researchers. It also works well when you are describing a particular study in detail. The second approach works well when you are discussing a general idea and especially when you want to include multiple citations for the same idea.

The third most common error in Table 11.2 has to do with the use of et al. This is an abbreviation for the Latin term et alia, which means “and others.” In APA style, if an article or a book chapter has more than two authors but fewer than six, you should include all their names when you first cite that work. After that, however, you should use the first author’s name followed by “et al.” If the article has only two authors then both should be included in every citation. If an article has six or more authors then you should only list the name of the first author followed by et al. each and every time you cite that work (even the first time). Here are some examples:

Recall that Mehl et al. (2007) found that women and men spoke about the same number of words per day on average.

There is a strong positive correlation between the number of daily hassles and the number of symptoms people experience (Kanner et al., 1981).

Notice that there is no comma between the first author’s name and “et al.” Notice also that there is no period after “et” but there is one after “al.” This is because “et” is a complete word and “al.” is an abbreviation for the word alia.