CASRAI Dictionary

Tag: APA

  • Citation Styles Compared: APA, MLA, Chicago, Vancouver

    Citation styles are standardised systems that prescribe how to format in-text citations and reference entries so that sources are credited consistently and can be retrieved reliably. The major styles — APA 7th edition, MLA 9th edition, the Chicago Manual of Style 17th edition, and Vancouver — share the same underlying data elements but differ in how those elements are ordered, punctuated and signalled in the text.

    Choosing a style is rarely a free decision: each discipline has settled on conventions, and journals, publishers and institutions specify which to use. The skill is applying the chosen style consistently, not memorising all of them.

    The four major styles at a glance

    Style Typical disciplines In-text format End-of-text list
    APA 7 Psychology, education, social sciences Author–date: (Author, Year) References, alphabetical
    MLA 9 Humanities, languages, literature Author–page: (Author 14) Works Cited, alphabetical
    Chicago 17 History, arts, some social sciences Notes-bibliography (footnotes) or author–date Bibliography or References
    Vancouver / ICMJE Medicine, biomedical sciences Numeric: [1] or superscript References, by order of citation

    APA 7th edition

    APA is an author–date style dominant in psychology and the social sciences. In-text citations carry the author surname and year, with a page number for direct quotations. The end list is titled “References”, alphabetised by surname, with a strong emphasis on the publication year because currency matters in empirical fields. DOIs are included as full https links.

    MLA 9th edition

    MLA serves the humanities, where the location of a phrase within a work often matters more than the year. Its in-text citation is author–page — (Author 14) — and the end list is titled “Works Cited”. MLA 9 organises an entry around a template of “core elements” (author, title of source, title of container, and so on), which makes it adaptable to non-traditional sources.

    Chicago Manual of Style 17th edition

    Chicago is distinctive for offering two complete systems:

    • Notes–bibliography. Used in history and the arts. Citations appear as numbered footnotes or endnotes, with a full bibliography at the end. This suits narrative disciplines where discursive notes add value.
    • Author–date. Used in the sciences and some social sciences, this variant works like APA — an in-text (Author Year) marker keyed to an alphabetical reference list.

    The existence of two Chicago systems is the most common source of confusion; always confirm which one a publisher expects.

    Vancouver and ICMJE

    Vancouver is the numeric style of medicine and the biomedical sciences, aligned with the recommendations of the International Committee of Medical Journal Editors (ICMJE). Sources are numbered in order of first appearance and listed in that order. This keeps dense clinical text uncluttered — a paper may cite dozens of sources per page — at the cost of hiding authorship behind a number. The mechanics of numeric versus author–date markers are detailed in in-text citations versus the reference list.

    Choosing the right style

    The decision usually follows a simple hierarchy:

    • Follow the journal or publisher first. Their author guidelines override personal preference.
    • Then follow your discipline. Social sciences default to APA, humanities to MLA, history to Chicago notes-bibliography, medicine to Vancouver.
    • Then follow your institution. A department or supervisor may mandate a house style.
    • Apply it consistently. Mixing styles within one document is itself an error, regardless of which you choose.

    Whatever style applies, the underlying data — author, year, title, container, persistent identifier — stays the same; only the presentation changes. Recording those elements accurately, and disambiguating authors with an ORCID iD, is what makes switching styles painless. This consistency also supports research integrity by keeping every claim traceable to a retrievable source. Practical help for applying a style is in our resources for authors.

    Frequently asked questions

    What is the difference between APA and MLA?

    APA uses author–date in-text citations and is standard in the social sciences, emphasising the year of publication. MLA uses author–page citations and is standard in the humanities, emphasising the location of material within a source. Their end lists are “References” and “Works Cited” respectively.

    Why does Chicago have two systems?

    Chicago offers a notes-bibliography system, suited to history and the arts where footnotes carry discursive comment, and an author–date system suited to the sciences. The two serve different writing cultures, so always confirm which variant a publisher requires.

    Which citation style should I use?

    Use the style your target journal, publisher or institution specifies; if none is mandated, follow your discipline’s convention. The most important rule is to apply a single style consistently throughout the document.

    Do all styles include a DOI?

    The major styles all accommodate persistent identifiers such as DOIs, because they make references durable and retrievable. The exact placement and formatting differ by style. See the CASRAI dictionary for standardised term definitions.

  • In-Text Citations vs Reference List Explained

    An in-text citation is the brief marker placed in the body of a document at the exact point where a source is used; the reference list is the full set of entries at the end that the markers point to. A citation system is the disciplined pairing of these two halves — a short signal in the text and a complete record at the back — so that any reader can move from a claim to its source and back again.

    The two halves are designed for different jobs. The in-text marker is kept minimal so it does not disrupt reading. The reference entry is kept complete so retrieval never fails. Neither works alone: a marker with no entry is a dead end, and an entry with no marker is an orphan.

    The two halves of a citation system

    Every mainstream citation system is built from the same pairing, even though the surface format differs:

    • In-text citation — an author–date marker such as (Okafor, 2020) or a numeric marker such as [7], sitting beside the borrowed material.
    • Reference list entry — the full bibliographic record, carrying author, year, title, container and a persistent identifier so the source can be located.

    This is the structural backbone described in our explainer on what a citation is.

    Author–date systems

    Author–date systems — used by APA and the author–date variant of Chicago — place the author surname and year of publication in the text. The reader matches that surname to the alphabetised reference list. A page number is added for direct quotations.

    For example, an in-text marker of (Okafor, 2020, p. 14) maps to a reference list entry beginning Okafor, A. (2020). Because the list is alphabetised, the reader scans to “O” and finds the full record. The strength of this system is that the reader sees author and date without leaving the sentence, which signals currency and authority inline.

    Numeric systems

    Numeric systems — Vancouver, used across medicine and many sciences under ICMJE conventions — replace the author–date marker with a number assigned in order of first appearance. The reference list is ordered numerically to match. An in-text marker of [7] sends the reader to the seventh entry in the list.

    Numeric markers keep the running text uncluttered, which suits papers with very many references. The trade-off is that the reader cannot tell who or when from the marker alone — they must turn to the list.

    Worked example: the same source, two systems

    System In-text marker Reference list entry (schematic)
    APA 7 (author–date) (Okafor, 2020) Okafor, A. (2020). Title of work. Publisher. https://doi.org/…
    Vancouver (numeric) [1] 1. Okafor A. Title of work. Publisher; 2020. Available from: https://doi.org/…

    Note how the data elements — author, year, title, publisher, DOI — are identical; only the order, punctuation and the form of the in-text marker change. That stability of elements beneath varying surface format is the central insight of comparing citation styles.

    How markers map to entries

    The integrity of a citation system depends on a clean one-to-one mapping. Every in-text marker must have exactly one matching reference entry, and — in a reference list, as opposed to a fuller bibliography — every entry must correspond to at least one in-text marker.

    • No orphan entries. A reference with no in-text marker suggests background reading that belongs in a bibliography, not a reference list.
    • No dangling markers. An in-text citation with no matching entry leaves the reader unable to retrieve the source.
    • Consistent identifiers. Author names should be disambiguated — an ORCID iD resolves the “which J. Smith?” problem — and persistent identifiers such as DOIs should resolve.

    Maintaining this mapping is also a matter of research integrity: a broken link between marker and entry undermines the verifiability that citation exists to provide.

    Choosing and applying a system

    Discipline usually dictates the choice: author–date for the social sciences and humanities, numeric for medicine and many natural sciences. Whatever the system, the rule is consistency — apply one set of conventions throughout, and let a reference manager enforce the marker-to-entry mapping for you. Practical guidance for getting this right lives in our resources for authors.

    Frequently asked questions

    What is the difference between an in-text citation and a reference?

    An in-text citation is the brief marker in the body of the text. A reference is the full entry in the reference list that the marker points to. They are two halves of one citation: the marker signals where a source is used, and the entry lets the reader retrieve it.

    How do numeric and author–date systems differ?

    Author–date systems put the author surname and year in the text and alphabetise the reference list. Numeric systems use a number assigned in order of first appearance and order the list to match. Numeric markers are more compact; author–date markers show authorship and currency inline.

    Should every reference list entry have an in-text citation?

    Yes, in a reference list. A reference list contains only sources actually cited, so every entry should map to at least one in-text marker. Background reading that was not cited belongs in a bibliography instead.

    Where can I check standardised definitions of these terms?

    The CASRAI dictionary provides standardised definitions, and our comparison of citation styles shows how different systems format the same source.

  • How to Cite a Website Correctly

    How to cite a website comes down to capturing five pieces of metadata — author, title, site name, date and URL — plus an access date, then formatting them for your chosen style. Because web pages can change or vanish, the access date and a stable URL matter more than for print sources.

    Follow the steps below, then use the worked examples in APA, MLA and Harvard.

    Step 1: Record the metadata

    Before you format anything, gather:

    • Author — a person or, failing that, the organisation responsible.
    • Title — the title of the specific page, not the whole site.
    • Site name — the publisher or container.
    • Date — publication or last-updated date.
    • URL — the direct, stable link (a DOI or permalink if available).
    • Access date — the day you viewed it.

    Step 2: Identify the author or fall back sensibly

    If no individual is named, use the organisation as author. If even that is unclear, move the page title to the author position. Never invent an author. Our practitioner guide to citing sources covers these fallbacks in depth.

    Step 3: Format for your style

    The same metadata is arranged differently in each style. Worked examples:

    • APA: Smith, J. (2021, March 4). Patterns of research participation. Research Standards Hub. https://example.org/patterns
    • MLA: Smith, Jane. “Patterns of Research Participation.” Research Standards Hub, 4 Mar. 2021, example.org/patterns. Accessed 19 June 2026.
    • Harvard: Smith, J. (2021) Patterns of research participation. Available at: https://example.org/patterns (Accessed: 19 June 2026).

    For the full APA rules behind that example, see our APA essentials guide, and for the author-date logic, Harvard referencing.

    Step 4: Handle missing dates and authors

    Web pages often lack a clean date or byline. Standard substitutions:

    Missing element APA MLA / Harvard
    No date (n.d.) Omit date; rely on access date
    No author Use title in author position Use organisation, then title
    No page title Describe content in brackets Describe content in brackets

    The access date does real work here: it tells a reader which version of a changeable page you relied on.

    Step 5: Add the in-text citation

    Pair the reference with the in-text marker your style uses — (Smith, 2021) in APA and Harvard, (Smith) in MLA. Where there is no author, use a short form of the title. Numeric styles such as IEEE and AMA handle web sources with the same numbered markers they use for print.

    Step 6: Verify the link is stable

    Prefer a DOI or permalink over a long session URL. If the page may move, note that an archived copy exists. Consistency across all your web citations is the final check our for authors guidance recommends.

    How web citation fits the wider record

    Well-formed web references plug into structured metadata: controlled terms in our dictionary and contributor roles via CRediT describe the rest of an output. For more on formatting choices, see citation styles compared and the research outputs category.

    Frequently asked questions

    Do I always need an access date?

    MLA and Harvard recommend one for web pages; APA requires it only when the content is likely to change and is not archived. When in doubt, include it.

    What if there is no publication date?

    Use (n.d.) in APA, or omit the date and rely on the access date in MLA and Harvard. Do not guess a date.

    Should I cite the homepage or the specific page?

    Cite the specific page you used. Reserve the homepage URL for when you are referring to the site as a whole.

    How do I cite a page with no author at all?

    Move the title into the author position, or use the organisation responsible for the site. Never fabricate authorship.

  • APA Reference List Format: Worked Examples

    An APA reference list is the alphabetically ordered set of full source entries placed at the end of a document, each formatted with a hanging indent and corresponding to an in-text citation. It follows the author–date conventions of the Publication Manual of the American Psychological Association (7th edition). Every work cited in the text appears once in the list, and every entry in the list is cited at least once in the text — the two must match exactly.

    The reference list is where APA’s four-element logic — author, date, title, source — becomes a precise, repeatable format. If you are new to the author–date system, start with our APA 7th edition essentials before building a full list.

    The three formatting rules that govern every entry

    Three mechanical rules apply to the whole list. First, alphabetical order by the first author’s surname; works by the same author are then ordered by year, earliest first. Second, a hanging indent: the first line of each entry sits at the left margin and every subsequent line is indented, so surnames are easy to scan. Third, the list is double-spaced with no extra blank lines between entries, and titled “References”, centred and bold, on a new page.

    Worked examples by source type

    The table below shows a correctly formatted entry for each major source type. Author names and years are illustrative placeholders, but the punctuation, italics and ordering are exactly as APA 7 requires.

    Source type Worked example
    Journal article Smith, J. A. (2021). Open-access uptake in clinical trials. Journal of Research Standards, 14(3), 220–238. https://doi.org/10.1000/jrs.2021.0143
    Book Brown, T. R. (2019). Foundations of research integrity. Academic Press.
    Chapter in an edited book Lee, S. (2020). Data-sharing norms. In R. Patel (Ed.), Open science in practice (pp. 45–67). University Press.
    Website / web page Jones, R. B. (2022, March 4). Metadata standards for research outputs. Research Standards Institute. https://example.org/metadata-standards
    Dataset Patel, A., & Khan, M. (2021). Citation-coverage survey 2021 [Data set]. Open Data Repository. https://doi.org/10.1000/odr.2021.0099

    Reading the journal-article entry

    Take the journal example apart. The author block inverts the name and uses initials. The year sits in brackets. The article title is in sentence case and not italicised — only the first word and proper nouns are capitalised. The journal name and volume number are italicised; the issue number, in brackets, is not. The page range and DOI close the entry, with no full stop after the DOI. This single pattern, with small variations, drives most of the references you will ever write.

    Handling books, chapters and the publisher rule

    Books reverse the italics: now the title is italicised in sentence case, and the publisher closes the entry. APA 7 dropped the publisher’s city, so “Academic Press” stands alone. For a chapter, you cite the chapter author and chapter title first, then “In”, the editor(s) with initials before the surname, the italicised book title, the page range in brackets, and the publisher. Knowing exactly who is credited at chapter versus volume level matters for fair attribution of credit.

    Websites, datasets and DOI formatting

    Web pages need a specific date where available — year, month and day — and the name of the hosting organisation as the “source”. Datasets are cited as first-class outputs: author, year, italicised title, a bracketed format description such as [Data set], the repository name and a DOI. Treating data this way reflects the modern research-outputs landscape, where datasets, software and protocols are citable on their own terms.

    For DOIs, always use the full https://doi.org/ form, with no trailing punctuation. If an online source has no DOI but has a stable URL, give the URL; if the content is likely to change, add a retrieval date. A persistent identifier is what links your entry to the durable scholarly record.

    Ordering edge cases

    Two situations trip people up. When one author has several works in the same year, distinguish them with lowercase letters on the year — (2021a), (2021b) — ordered by title, and mirror those letters in the in-text citations. When alphabetising, treat “nothing before something”: Smith, J. comes before Smith, J. A. Single-author entries precede multi-author entries that begin with the same surname.

    Frequently asked questions

    Should every cited source appear in the reference list?

    Yes — with one exception. Standard in-text-only items such as personal communications (emails, interviews not recoverable by a reader) are cited in the text but not listed, because there is nothing the reader can retrieve. Everything recoverable must appear.

    How do I order two works by the same author?

    By year, earliest first. If the years are identical, add lowercase letters to the year and order alphabetically by title. Single-author works always come before that author’s collaborative works.

    Do I keep the hanging indent in a numbered or bulleted list?

    The reference list is never numbered or bulleted in APA. It is a plain, double-spaced list with a hanging indent on each entry. Numbered referencing belongs to other styles, such as Vancouver.

    Where can I confirm an unusual entry?

    For conference papers, theses, software or grey literature, check your institution’s APA guide or the Publication Manual. CASRAI’s author guidance and standards dictionary can help you decide how to describe an output before you format it.

  • APA Referencing Style Essentials (7th Edition)

    APA format is the author–date referencing style of the American Psychological Association, set out in the Publication Manual of the American Psychological Association (7th edition, 2020). It pairs a brief in-text citation — author surname and year — with a full, alphabetically ordered entry in a reference list at the end of the document. APA is the dominant style across psychology, education, nursing and the social and behavioural sciences.

    Because APA is built on the author–date principle, every claim that draws on a source carries a signal the reader can resolve immediately: who said it, and when. The year matters because evidence in these disciplines ages, and recency is part of how readers judge relevance. To understand where APA sits among the major systems, it helps to read it alongside our overview of how APA, MLA, Chicago and Vancouver compare.

    How APA in-text citation works

    APA in-text citations name the author and the year, and add a page or paragraph number for direct quotations. Two formats exist. A parenthetical citation places everything in brackets: (Smith, 2021). A narrative citation weaves the author into the sentence and brackets only the year: Smith (2021) argued that… For a direct quote, add a locator: (Smith, 2021, p. 14).

    Works by two authors name both every time, joined by an ampersand inside brackets — (Smith & Jones, 2020) — or by “and” in narrative form. Works by three or more authors use “et al.” from the first mention: (Smith et al., 2019). This shortening was one of the headline changes in the 7th edition.

    Anatomy of an APA reference entry

    Every full reference answers four questions in a fixed order: Who (author), When (date), What (title), and Where (source). A journal-article entry illustrates the pattern:

    Smith, J. A., & Jones, R. B. (2021). Measuring open-access uptake in clinical research. Journal of Research Standards, 14(3), 220–238. https://doi.org/10.1000/jrs.2021.0143

    Element Example Rule
    Author Smith, J. A., & Jones, R. B. Surname, then initials; invert all authors; ampersand before the last
    Date (2021). Year of publication in brackets
    Title Measuring open-access uptake in clinical research. Sentence case; article titles not italicised
    Source Journal of Research Standards, 14(3), 220–238. Journal name and volume italicised; issue in brackets; page range
    DOI https://doi.org/10.1000/jrs.2021.0143 Presented as a full clickable URL

    Authorship order in the reference list is not cosmetic — it carries credit. The conventions for who appears, and in what order, connect directly to broader debates about contribution and credit and the standards around authorship that CASRAI documents.

    Common source types

    The four-part skeleton flexes to fit different materials. A book gives author, year, italicised title in sentence case, and publisher: Brown, T. (2019). Foundations of research integrity. Academic Press. A chapter in an edited book adds the editors and book title: Lee, S. (2020). Data-sharing norms. In R. Patel (Ed.), Open science in practice (pp. 45–67). University Press. A web page gives author, date, italicised title and the site, then the URL. A dataset is treated as a recoverable output with author, year, title, a bracketed description such as [Data set], the repository, and a DOI.

    DOIs as URLs

    One of the clearest shifts in APA 7 is DOI formatting. A digital object identifier is now always presented as a full https://doi.org/ URL rather than the older “doi:” prefix. No full stop follows the DOI or URL, because trailing punctuation can break a link. When a DOI exists, include it for every source type that has one, online or print. The DOI is the source’s persistent address — closely related to the role of a stable identifier in the wider scholarly record.

    What changed in the 7th edition

    The 7th edition (2020) made several practical changes. Publisher locations were dropped from book references. The “et al.” rule now applies from the first citation for three or more authors, and the reference list may name up to 20 authors before truncating. The phrase “Retrieved from” before URLs was removed unless a retrieval date is genuinely needed. Singular “they” is endorsed as an inclusive pronoun. And the manual added explicit, format-specific guidance for student papers versus professional manuscripts.

    Frequently asked questions

    Do I need a page number for every APA citation?

    No. A page or paragraph number is required only for direct quotations and is recommended when you point to a specific passage. Paraphrased material needs author and year but no locator, though giving one is courteous when paraphrasing from a long work.

    How do I cite a source with no author?

    Move the title to the author position. For an in-text citation, use the first few words of the title in italics or quotation marks, matching how the work is formatted in the reference list, followed by the year. Use “n.d.” for no date.

    Is APA the same as Harvard referencing?

    They share the author–date family resemblance, but they are not identical. Harvard is a style family with many institutional variants, whereas APA is a single, centrally published standard with precise rules. Always follow the specific guide your publisher or institution names.

    Where can I check the correct entry for an unusual source?

    Consult the Publication Manual directly, or your institution’s APA guide, for materials such as conference papers, theses, software and social media. CASRAI’s guidance for authors and our research-standards dictionary can help you reason about how an unfamiliar output should be described and credited.