Author-date citations, the References page, DOIs, journal articles, books, online sources, and complete APA paper formatting — the documentation system of the social sciences
When researchers write for publication, they do not simply hand over their findings in whatever form they choose. They follow agreed-upon rules for organizing information, citing sources, and formatting documents. These rules exist so that readers from the same discipline can navigate any paper efficiently, locate original sources with confidence, and evaluate the quality of evidence without wasting time deciphering an unfamiliar system.
APA style is one of the most widely used documentation systems in the world. Developed by the American Psychological Association, it was created to meet the specific needs of researchers in psychology, education, nursing, social work, communications, and related fields. Today it is required in hundreds of disciplines and thousands of institutions. Whether you are writing a research paper for a psychology course, a literature review for a sociology class, or a report for a public health program, there is a good chance your instructor expects APA documentation.
This chapter teaches APA style from the ground up. It explains what APA is and why it was designed the way it was. It walks through in-text citations in detail, showing how to handle sources with one author, multiple authors, no author, organizations as authors, and direct quotations. It then explains the APA References page, covering the most common source types students encounter. Finally, it addresses general APA paper formatting.
APA is the required format in most social science, health, education, and behavioral science courses. Mastering it early means every paper you submit in those fields will meet professional standards. More importantly, understanding why APA works the way it does helps you use it correctly in situations no reference sheet can anticipate.
Before learning any specific formatting rules, it helps to understand what documentation systems are trying to accomplish. Academic writing is a conversation. When researchers publish their findings, they build on the work of other researchers who came before them. They respond to existing theories, challenge previous conclusions, add new data, and refine old models. Because so much academic writing depends on prior work, readers need a reliable way to trace ideas back to their original sources.
A documentation system is a standardized set of rules for acknowledging those sources. It tells writers exactly how to record the essential information about every source they use, and it tells readers exactly where to look to find original material. When everyone in a discipline follows the same rules, research becomes more transparent, more verifiable, and more trustworthy.
| Documentation System | Developed By | Primary Fields | In-Text Format |
|---|---|---|---|
| APA | American Psychological Association | Social sciences, education, nursing, health | Author, Year |
| MLA | Modern Language Association | Literature, language, humanities | Author, Page |
| Chicago | University of Chicago Press | History, humanities, some social sciences | Footnotes or Author, Year |
APA style was first published in 1929 as a brief article in the journal Psychological Bulletin, offering guidelines for the preparation of manuscripts in psychology. It has been revised many times since then. The current edition, the seventh, was published in 2019 and introduced several updates to simplify and modernize the system.
The most distinctive feature of APA documentation is its author-date citation format. Every in-text citation includes the author's last name and the year of publication. This reflects the priorities of scientific and social-scientific research. In these fields, the date of a study matters enormously. A reader encountering a citation can immediately see who conducted the research and when — allowing them to judge how current the evidence is.
Compare this to literature scholarship, where a 1958 critical essay on Shakespeare may be just as relevant as one written last year. In literary studies, the date of a secondary source is usually less important than who wrote it and what they argued. MLA style, which does not include the year in its in-text citations, reflects that different set of priorities.
In social science research, findings can be overturned by new studies. A reader seeing "(Smith, 1995)" knows immediately to check whether newer research has updated or revised that finding. The date is not just a formality — it is information the reader needs to evaluate the quality and currency of the evidence.
Every time you use information from a source in APA style, you must acknowledge that source within the sentence or passage where you use it. This acknowledgment takes the form of a brief parenthetical note or a signal phrase containing the author's last name and the year of publication. This in-text citation connects directly to the full entry on the References page at the end of your paper.
The relationship between in-text citations and References entries is essential. An in-text citation is never complete by itself — it is a pointer. Every source you cite in the body of your paper must appear in the References list. Every source in your References list must be cited somewhere in the body of your paper. There should be no orphaned citations and no uncited references.
Paraphrase: Author's last name, year
Direct quotation: Author's last name, year, p. page number
Both can appear as parenthetical citations or be integrated through a signal phrase. The year always follows the author's name in parentheses.
When you paraphrase a source — expressing the author's ideas in your own words — you cite the author's last name and the year of publication. The citation typically appears in parentheses at the end of the sentence, before the period.
When you quote a source word for word, APA style requires three pieces of information: the author's last name, the year of publication, and the page number. The page number is preceded by p. for a single page or pp. for a range of pages.
A quotation of forty words or more is formatted as a block quotation. Block quotations are indented half an inch from the left margin, have no quotation marks around them, and are followed by the citation in parentheses after the final period — which is the reverse of normal sentence punctuation.
In a block quotation, the period comes before the parenthetical citation, not after. This is the opposite of how regular sentence citations work: ". . . more capable peers. (Vygotsky, 1978, p. 86)" — the period is inside the quote, and the citation follows the closing period of the block.
| Number of Authors | In-Text Format | Example |
|---|---|---|
| One author | Last name, year | (Kahneman, 2011) |
| Two authors | Last name & Last name, year | (Kahneman & Tversky, 1979) |
| Three or more authors | First author's last name et al., year | (Bandura et al., 1977) |
For two authors, always cite both names, connected by an ampersand (&) in a parenthetical citation or by the word and in a signal phrase: Kahneman and Tversky (1979) demonstrated that...
For three or more authors, cite only the first author's name followed by et al. (Latin for "and others") from the very first citation. APA 7 simplified this from the previous edition, which required listing up to five authors before using et al.
Use the ampersand (&) only inside parenthetical citations: (Kahneman & Tversky, 1979). When authors' names appear in the flow of a sentence, use the word "and": "Kahneman and Tversky (1979) found that..." Using & in the sentence itself is incorrect in APA style.
The References page appears at the end of your paper. It contains a complete, alphabetically organized list of every source you cited in your paper. The purpose of the References page is to give readers everything they need to locate each source independently: the author, the date, the title, the publication information, and — where applicable — a link or database identifier.
The APA References page is not the same as a bibliography. A bibliography may include sources you read but did not cite. A References list includes only the sources you actually cited in the paper. Every entry must correspond to at least one in-text citation, and every in-text citation must correspond to an entry.
• Begin on a new page after the final page of your paper.
• Center the word References at the top in bold.
• List all entries alphabetically by the first author's last name.
• Use a hanging indent: first line flush left, all subsequent lines indented half an inch.
• Double-space all entries with no extra space between them.
• Use sentence case for article and chapter titles; use title case for journal names and book titles.
Every APA entry follows this pattern: Author, A. A. (Year). Title of work. Publisher/Source information. The who, when, what, where structure is consistent — only the specific contents change for different source types.
APA style was developed in a research context where journal articles are the primary medium for sharing findings. Knowing how to cite a journal article accurately is the most important citation skill in APA style.
A Digital Object Identifier, or DOI, is a permanent alphanumeric code assigned to a piece of scholarly content. It functions like a digital address that never changes, even if the document moves to a different server or website. In APA 7, DOIs are formatted as hyperlinks:
When a DOI is available, always include it. When no DOI is available, include the URL of the journal's home page or a freely available version online. If the article comes from a subscription database and has no DOI, end the entry after the page range.
The article title is in sentence case (only first word and proper nouns capitalized). The journal name is in title case and italicized. The volume number is also italicized; the issue number in parentheses is not.
When you use a specific chapter from an edited book, you must cite the chapter author and title separately from the book's editor and title. This format is more complex than other entries but follows a consistent logic: the chapter author appears in the author position, and the book editor and title appear in the container section.
The chapter title is in sentence case and has no quotation marks or italics. The word In precedes the editor's name. The editor's name appears in normal order (initials first, last name second) — unlike the chapter author. The abbreviation Ed. appears in parentheses. The book title is italicized and in sentence case. Page range appears in parentheses after the book title.
Research reports published by government agencies, research institutes, nonprofits, and professional organizations are common sources in social science, public health, education, and policy writing. These reports often have organizational authors rather than individual authors.
The web presents particular challenges for documentation. Websites may lack clear authorship, publication dates, or stable URLs. Content may change or disappear after you access it. APA 7 introduced updates to handle online sources with the general principle: give as much identifying information as you can, and prioritize permanence where possible.
| Missing Element | Solution |
|---|---|
| No author | Begin the entry with the title of the page in the author position. |
| No date | Use n.d. in the date position. Add a retrieval date if content changes frequently. |
| No title | Use a description in square brackets: [Description of the content]. |
The way your paper looks on the page communicates something to your reader. A correctly formatted paper signals that you understand the conventions of the discipline and have given attention to presentation as well as content. APA formatting guidelines create consistency across documents, make papers easier to read, and ensure that submission-ready manuscripts look the same regardless of the word processor used to create them.
| Element | APA Specification |
|---|---|
| Margins | One inch on all sides |
| Font | Times New Roman 12pt, Calibri 11pt, Arial 11pt, or Georgia 11pt |
| Line spacing | Double-spaced throughout — including title page, abstract, body, and References |
| Paragraph indentation | Half-inch indent for first line of each paragraph (use Tab key, not spacebar) |
| Alignment | Left-aligned; do not use full justification |
| Page numbers | Upper right corner of every page; begins with title page as page 1 |
The APA title page for a student paper includes the paper title (centered, bold, title case), the author name(s), institutional affiliation, course information, instructor name, and assignment due date — all centered. The title is in the upper half of the page. The title page is its own page (page 1); the paper begins on page 2.
Papers submitted for journal publication include a running head — a shortened version of the title in all capitals, placed in the left side of the header. For most student papers submitted in courses, the running head is not required. Check with your instructor before adding one.
An abstract is a brief summary of the paper, typically between 150 and 250 words. It appears on its own page (page 2) after the title page. The word Abstract is centered and bold at the top. The abstract itself is not indented and is written as a single paragraph. Not all student papers require an abstract — your instructor will specify. Below the abstract, you may be asked to include 3 to 5 keywords:
APA uses a five-level heading system. Most student papers use only two or three levels. Do not use the word "Introduction" as a heading — the opening section is understood to be the introduction without labeling.
| Level | Format | Use |
|---|---|---|
| Level 1 | Centered, bold, title case | Major sections |
| Level 2 | Left-aligned, bold, title case | Subsections within Level 1 |
| Level 3 | Left-aligned, bold italic, title case | Subsections within Level 2 |
Each table and figure is numbered sequentially (Table 1, Table 2; Figure 1, Figure 2) and includes a title and explanatory note. The word Table or Figure followed by the number appears in bold above the table or figure. A descriptive title in italics appears on the line below. A note appears below the table in regular type, beginning with the word Note in italics followed by a period.
Alphabetize letter by letter, ignoring spaces. Mc and Mac are treated as spelled. When the same author has multiple entries, list them from earliest to most recent. When the same author has multiple publications in the same year, alphabetize by title and add letters to the year: 2018a, 2018b. When no author is listed, alphabetize by the first significant word of the title.
For each situation below, write a correct APA in-text citation. Include both the parenthetical version and a signal phrase version.
Using the information below, write a correctly formatted APA reference entry for each source.
Each reference entry below contains at least one error. Identify the error and write the corrected entry.
Identify all errors. Hints: author name format, article title capitalization, volume italics, DOI format.
Identify the errors. Hints: author name format, book title punctuation, publisher location.
Identify the errors. Hints: article title capitalization, journal name italics, volume number italics.
Below are four sources in random order without correct formatting. Rewrite them as a correctly formatted APA References page: alphabetical order, correct case, italics, hanging indents, and punctuation.
Use this checklist before submitting any paper that requires APA documentation.
Chapter 40 introduced APA style, the documentation system of the social and behavioral sciences. Chapter 41 turns to Chicago style — the system most commonly required in history, classical studies, and certain humanities fields. Chicago style offers two documentation options: notes-bibliography style (which uses footnotes or endnotes rather than in-text citations) and author-date style (which resembles APA). Understanding when and why each system is used will give you the documentation versatility to write in any academic field.