CASRAI Dictionary

Tag: referencing

  • Chicago and Vancouver Referencing Styles Explained

    Chicago style is the referencing system of The Chicago Manual of Style (17th edition), offering two variants — notes-bibliography, which uses footnotes or endnotes, and author–date, which uses parenthetical citations. Vancouver style, codified in the ICMJE Recommendations, is a numeric system in which sources are numbered in the order they first appear and listed in that numeric order. Chicago dominates history, the arts and publishing; Vancouver is standard across medicine and the biomedical sciences.

    These two styles bracket the range of approaches a researcher will meet. Chicago is the most flexible of the major systems; Vancouver is the most compact. Seeing them side by side clarifies why a discipline chooses one referencing logic over another — a theme we develop in our broader comparison of APA, MLA, Chicago and Vancouver.

    Chicago notes-bibliography

    In the notes-bibliography variant, a superscript number in the text points to a footnote (or endnote) carrying the full source details, and a parallel bibliography at the end lists all sources alphabetically. The note and bibliography entry differ slightly in format. A first footnote gives full detail:

    1. Jane Smith, Foundations of Research Integrity (London: Academic Press, 2019), 142.

    The matching bibliography entry inverts the author’s name and uses full stops rather than commas and brackets:

    Smith, Jane. Foundations of Research Integrity. London: Academic Press, 2019.

    Subsequent references to the same work are shortened to author, short title and page — Smith, Foundations, 88 — which keeps the notes readable. This variant suits the humanities because footnotes can carry commentary as well as citations, letting a historian discuss a source without breaking the main argument.

    Chicago author–date

    The author–date variant works much like APA: a parenthetical (Smith 2019, 142) in the text points to an alphabetical reference list. It is favoured in the sciences and social sciences when Chicago is the house style. The reference-list entry resembles the bibliography entry but moves the year forward: Smith, Jane. 2019. Foundations of Research Integrity. London: Academic Press. Choosing between Chicago’s two variants is normally dictated by your discipline or publisher, not personal preference.

    Vancouver and the ICMJE Recommendations

    Vancouver style assigns each source a number the first time it is cited, in brackets or as a superscript — [1] or 1 — and reuses that number on every later citation of the same source. The reference list is then ordered numerically, by order of first appearance, not alphabetically. The ICMJE Recommendations specify the format, including abbreviated journal titles and a distinctive author style with no full stops after initials:

    1. Smith J, Jones R. Open-access uptake in clinical trials. J Res Stand. 2021;14(3):220–38.

    Vancouver’s numeric compactness suits biomedical papers, which often carry dozens of references and value an unobtrusive in-text marker. Because the numbering follows appearance order, inserting a new citation mid-draft renumbers everything after it — which is why reference-manager software is near-universal in the field.

    Comparing the three at a glance

    Feature Chicago notes-bib Chicago author–date Vancouver
    In-text marker Superscript note number (Author Year, page) Bracketed number [1]
    List order Alphabetical bibliography Alphabetical reference list Numeric, by first appearance
    Typical disciplines History, arts, publishing Sciences, social sciences Medicine, biomedical sciences
    Governing standard Chicago Manual 17th ed. Chicago Manual 17th ed. ICMJE Recommendations

    Why the differences matter

    The choice of system is not arbitrary decoration. A footnote system lets a humanities scholar annotate and qualify a source in place; a numeric system lets a clinician cram a dense evidence base into a tight word limit; an author–date system keeps the year visible where recency is part of the argument. Each encodes a different relationship between the writer’s text and the scholarly record. Underneath all of them, the obligations to assign credit accurately and to record authorship honestly are the same — only the surface format changes.

    If you are moving between disciplines and meeting an unfamiliar style, CASRAI’s guidance for authors can help you map an output onto whichever convention a new editor requires.

    Frequently asked questions

    Is Chicago author–date the same as APA?

    They are close cousins but not identical. Both use author–date in-text citations and an alphabetical list, but punctuation, capitalisation and the treatment of titles differ. Chicago title-cases titles and has its own publisher conventions; APA uses sentence case for article titles. Always follow the specific manual your editor names.

    How does Vancouver handle a source cited several times?

    It keeps the original number. A source numbered [3] on first appearance is cited as [3] every subsequent time, and appears once in the reference list at position 3. The number is fixed to the source, not to the location of the citation.

    When should I use notes-bibliography rather than author–date Chicago?

    Use notes-bibliography in the humanities and wherever footnotes are expected to carry discussion as well as citations. Use author–date in the sciences and social sciences, or wherever a journal’s house style specifies it. The decision is set by the publisher, not the writer.

    Do these styles require DOIs?

    Both increasingly expect a DOI where one exists, and the ICMJE Recommendations encourage including it for journal articles. A DOI anchors the entry to a persistent address, which matters as much in numeric and notes systems as in author–date ones.

  • 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.

  • Citing Secondary Sources: The ‘As Cited In’ Rule Explained

    A secondary citation occurs when you refer to a source you have not read yourself, having encountered it only through another author’s discussion. Scholarly convention requires you to be transparent about this using the “as cited in” (or “qtd. in”) formula. The guiding principle is simple: cite what you actually read, and wherever possible track down and cite the original source instead.

    Why the rule exists

    If author B quotes or summarises author A, and you have read only B, you cannot vouch for what A really said. B may have paraphrased loosely, quoted selectively or made an error. Citing A directly as if you had read it misrepresents your sources and risks propagating a mistake. The “as cited in” convention keeps the record honest by showing the reader the chain: the original idea came from A, but you read it in B. This honesty is part of the integrity of the scholarly record.

    Read the original where you can

    Secondary citation is a fallback, not a convenience. Before using it, try to obtain the original — through your library, interlibrary loan, or a DOI lookup. Reading the original lets you confirm the quotation, see its context and cite it directly. Use “as cited in” only when the original is genuinely unavailable (out of print, untranslated, lost).

    How major styles handle it

    The styles agree on the principle but differ in wording and in which source goes in the reference list. The general rule across styles is that the reference-list entry is for the work you actually read (the secondary source).

    Style In-text form Reference list
    APA (Smith, 1999, as cited in Jones, 2020) Jones (the source you read) only
    MLA (qtd. in Jones 45) Jones (the source you read) only
    Chicago (notes) Smith, [work], quoted in Jones, [work] Both may appear, with the relationship shown
    Harvard (author–date) (Smith 1999, cited in Jones 2020) Jones (the source you read) only

    Always confirm the exact punctuation against your specific style edition, as details vary between versions. A reference manager can format the entry, but secondary citations are a classic case where you must check the output by hand.

    Worked examples

    APA, in text: Early work on data reuse argued that incentives drive deposit (Smith, 1999, as cited in Jones, 2020). Only Jones (2020) appears in your reference list.

    MLA, in text: One critic calls the dataset “the backbone of reproducibility” (qtd. in Jones 45). Only Jones appears on the Works Cited page.

    In both cases the message to the reader is identical: the idea originates with Smith, but you read it in Jones, and Jones is what you can actually verify. For how this fits into building a full reference list, see our guide to compiling a bibliography.

    Good practice

    Minimise secondary citations; prefer originals; quote B’s reading of A accurately; and never silently cite A as if you read it. When you must use “as cited in”, be precise about page numbers from the source you read. These habits, alongside accurate reference checking, support honest scholarship. See our author resources, the dictionary and the research-outputs hub for more.

    Frequently asked questions

    What does ‘as cited in’ mean?

    It signals that you are citing an original source (the primary) that you encountered only through another work (the secondary) which you actually read. It keeps your sourcing honest by showing you did not read the original directly.

    Which source goes in my reference list?

    In most author–date styles, only the source you actually read — the secondary source — appears in the reference list. The original is named in the in-text citation but not listed, because you cannot verify it directly. Chicago notes style may show both.

    Is using ‘qtd. in’ the same as ‘as cited in’?

    Effectively yes. “Qtd. in” (quoted in) is the MLA wording, while “as cited in” is the APA and Harvard wording. Both indicate a secondary citation; use the form your style requires.

    When should I avoid secondary citation entirely?

    Whenever you can obtain the original. Reading the primary source lets you verify the quotation and context and cite it directly, which is always preferable. Reserve secondary citation for sources that are genuinely unavailable.

  • How to Cite Sources: A Practitioner’s Step-by-Step Guide

    To cite a source, identify what type of source it is, capture its key metadata (author, date, title and where it was published), choose the referencing style your work requires, then build both an in-text citation and a matching reference entry — and finally check the entry against the original. The same five-step workflow applies whether you are using APA, MLA, Chicago or Vancouver; only the formatting at the end changes.

    Citation is not a clerical afterthought. It is how you connect your argument to the wider scholarly record, give fair credit to others, and let readers verify your claims. Treating it as a repeatable process — rather than something to patch in at the end — is the single biggest improvement most writers can make.

    The five-step workflow

    1. Identify the source type. Is it a journal article, a book, a chapter in an edited book, a web page, a report, a dataset or a thesis? The type determines which metadata you need and how the entry is shaped. A journal article needs a volume and issue; a book needs a publisher; a dataset needs a repository.
    2. Capture the metadata. Record, at minimum: author(s), year (and full date for web sources), title of the source, the larger work or publisher it appears in, and a locator — page range, DOI or stable URL. Capture this as you read, not later, when the tab is closed and the detail is gone. A DOI, where one exists, is the most valuable single field, because it is a persistent address into the record.
    3. Choose the style. Use the style your publisher, journal or institution mandates — APA for much of the social sciences, MLA for the humanities, Chicago in history and publishing, Vancouver in biomedicine. If no style is specified, pick one and apply it consistently. Never mix styles within one document.
    4. Build the in-text citation and reference entry. Create the brief in-text marker and the full entry together, so the two always match. In author–date styles the marker is author and year; in numeric styles it is a bracketed number; in notes styles it is a footnote.
    5. Check accuracy. Verify author spellings, the year, the page range and especially the DOI against the original source. Confirm that every in-text citation has a reference-list entry and vice versa. Inaccurate citations break the chain of verification and can edge into plagiarism when a source is misattributed.

    A worked example across three styles

    Suppose you are citing a journal article by Jane Smith, published in 2021, titled “Open-access uptake in clinical trials”, in volume 14, issue 3 of the Journal of Research Standards, pages 220–238, with a DOI. The metadata is identical; only the rendering differs.

    Style In-text Reference / list entry
    APA 7 (Smith, 2021) Smith, J. (2021). Open-access uptake in clinical trials. Journal of Research Standards, 14(3), 220–238. https://doi.org/10.1000/jrs.2021.0143
    MLA 9 (Smith 224) Smith, Jane. “Open-Access Uptake in Clinical Trials.” Journal of Research Standards, vol. 14, no. 3, 2021, pp. 220–38.
    Vancouver [1] 1. Smith J. Open-access uptake in clinical trials. J Res Stand. 2021;14(3):220–38.

    The same five steps produced all three; the only step that diverged was the fourth. This is why capturing complete metadata once, well, pays off no matter which style a journal later demands.

    Common mistakes and how to avoid them

    The most frequent errors are missing metadata (no DOI, no issue number), inconsistent style within one document, and a mismatch between in-text citations and the reference list. A subtler error is citing a source you have not actually read — relying on someone else’s summary while implying first-hand knowledge. If you must cite a work you have only seen quoted, cite it as a secondary source and be transparent. Accurate, honest citation is a core expectation of research integrity, as defined by bodies such as COPE.

    Tools, and their limits

    Reference managers and the “cite” buttons on databases speed up step four, but they do not replace step five. Auto-generated citations routinely garble author initials, drop subtitles, mis-capitalise titles or invent the wrong style variant. Use the tools to draft, then verify by hand against the source. Our guidance for authors and the CASRAI standards dictionary can help you reason about how to describe outputs that the tools handle poorly, such as datasets, software and protocols.

    Frequently asked questions

    What is the minimum information I need to cite a source?

    Author, year (or full date for web content), title, the larger work or publisher, and a locator such as a page range, DOI or stable URL. If any of these is genuinely absent, every style provides a substitute — for example, moving the title to the author position when there is no named author.

    How do I cite a source I found quoted in another work?

    Cite it as a secondary source. Name the original work and indicate that you read it via the secondary one, using your style’s “as cited in” convention. Better still, find and read the original where you can, then cite it directly.

    Can I mix citation styles in one document?

    No. Consistency is part of what makes citations readable and verifiable. Choose one style and apply it to every citation, every entry and every locator throughout the document.

    Does citing always prevent plagiarism?

    Citing is necessary but not sufficient. You must also signal borrowed wording with quotation marks or proper paraphrasing. A citation attached to copied text without quotation marks is still plagiarism — citing and quoting are two separate obligations.

  • Citation Accuracy: Why Generated References Always Need Checking

    A citation generator is a tool that takes bibliographic metadata — author, title, year, source, DOI — and applies the rules of a citation style to produce a formatted reference. It saves time, but it does not understand the source; it formats whatever data it is given. Because that data is frequently incomplete or wrong, every generated reference must be checked against the original before you rely on it.

    How a citation generator works

    Generators work in one of two ways. Some ask you to type the details into a form. Others retrieve metadata automatically from a DOI, an ISBN, a database record or a web page’s embedded tags. The tool then applies a style template — the punctuation, ordering, capitalisation and abbreviation rules of APA, MLA, Chicago, Vancouver or another style — and outputs the reference. The same engine drives the cite-while-you-write features in reference management software. The crucial point is that the generator formats metadata; it cannot supply facts it was never given.

    Where generated references go wrong

    Common errors fall into predictable categories.

    Problem Why it happens What to check
    Missing fields Source metadata lacks a page range, issue number or DOI Compare against the published article
    Capitalisation errors Title stored in all caps or title case; style wants sentence case Proper nouns, sentence vs title case
    Author-name errors Initials, hyphens or multi-part surnames mishandled Order, initials, particles like “van”
    Wrong source type A chapter imported as a whole book, a preprint as an article Item type and container title
    Style edge-cases Templates miss rare rules (corporate authors, et al. thresholds) The style guide’s specific rule
    URL instead of DOI Generator grabbed a fragile link Substitute the persistent identifier

    That last row matters for durability: prefer a DOI over a plain URL wherever one exists.

    Why edge-cases trip up generators

    Citation styles contain many special rules — how to handle an organisation as author, when to use “et al.”, how to cite a translated work, how to format a dataset or a preprint. Generator templates cover the common cases well but often miss the rare ones. They also cannot know context: only you can tell whether you read a chapter or the whole book, or whether a source is a secondary citation that needs the “as cited in” treatment.

    Good practice for accurate references

    Treat the generator as a first draft. After it produces a reference: confirm the author names and order against the source; check the title’s capitalisation against your style; verify year, volume, issue and page range; replace any fragile URL with a DOI; and confirm the item type. Build the habit of checking as you collect, not the night before submission. Accurate referencing is part of the integrity of the scholarly record, and our author resources and dictionary set out the conventions in detail. For broader context, see our research-outputs hub.

    Frequently asked questions

    Are citation generators reliable?

    They are reliable at applying formatting rules but not at guaranteeing correct content. The output depends entirely on the metadata supplied, which is often incomplete or contains errors, so every generated reference should be verified against the original source.

    Why does the generator capitalise my title wrong?

    Because the stored metadata may use a different case from the one your style requires, and the template cannot reliably tell proper nouns from ordinary words. You must correct capitalisation by hand against the style’s rule.

    Do reference managers fix these problems automatically?

    Partly. They store metadata and apply styles, but they import the same imperfect data, so they reproduce the same errors. The remedy is the same: check each entry against the source.

    What is the single most important check?

    Compare the generated reference field by field with the actual source — authors, title, year, volume, pages and identifier. If a DOI exists, ensure it is present and resolves.

  • 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.