The et al. cutoff: six authors is a journal rule, not a style default.
Waraq · July 11, 2026 · RULE OF THE WEEK
List the number of authors your target journal's reference spec names, and treat every other number as a default the journal can override. PLOS ONE and Frontiers in Neurology both want the first six authors followed by et al. APA 7 reference entries carry up to twenty names, and journals following the AMA Manual of Style cut to the first three once a paper has more than six authors. The citation style hands you a starting point. The journal's guide for authors hands you the rule.
Why do et al. rules differ between journals on the same base style?
Because each journal publishes its own reference spec, and the technical check at submission enforces that spec rather than the style manual it descends from.
Vancouver is the clearest case. It is less a single standard than a family of house styles descended from the ICMJE recommendations, whose sample references, maintained by the US National Library of Medicine, list the first six authors followed by et al. when a paper has more than six. A journal adopting Vancouver inherits that default, then edits it. Some keep six. Journals on the AMA Manual of Style, another numbered biomedical style, list the first three once the count passes six. So two journals can both say "numbered references, cited in order of appearance" and still want differently shaped entries for the same cited paper. Which base style a journal uses, Vancouver or APA, tells you how citations are keyed in the text. It does not tell you where the author list stops.
The same thing happens with abstract word limits, where journals sharing a format still set different caps. Knowing the base style narrows the possibilities; it never settles them.
What does PLOS ONE require in the reference list?
The first six authors, then et al. PLOS ONE's submission guidelines state the rule in one sentence: "Use the numbered citation (citation-sequence) method and list the first six authors, et al."
Citation-sequence means references are numbered in the order they first appear and cited in the text by that number in square brackets. Author names never appear in the citation itself, which makes the six-author rule a pure reference-list formatting requirement. A reader scanning your bibliography sees six surnames and et al. for a consortium paper with forty contributors, and the entry is compliant. Spell out all forty and the entry is wrong, at this journal, even though every name is accurate.
What does Frontiers in Neurology require for the same entry?
Also six authors, but stated in its own spec with its own additions. The Frontiers in Neurology author guidelines say: "The names of the first six authors followed by et al. and the DOI (when available) should be provided in references."
The number happens to match PLOS ONE here, and that is the trap. Nothing guarantees the match. The two journals wrote separate sentences in separate documents, and Frontiers attached a second requirement, the DOI, that the PLOS ONE rule never mentions. Move the same manuscript to a journal on the AMA Manual and the cutoff drops to three. Send it to an APA-style journal and a seven-author reference suddenly lists all seven names, because APA 7 entries run to twenty authors before an ellipsis appears. One paper, one bibliography, at least three correct shapes depending on the destination.
Reading the two rules side by side builds the habit that protects you. Ask what this journal wrote down, never what the style usually does.
Is the in-text et al. the same rule as the reference-list cutoff?
No. They are separate rules that happen to share an abbreviation, and mixing them up produces confident errors.
In numbered styles like the two above, the in-text citation is a numeral, so the author question barely arises in your prose. When you name authors narratively, as in "Alvarez and colleagues reported," that is a writing choice, and the reference spec has nothing to say about it. In author-date styles the split is sharper. APA 7's in-text rule shortens any work with three or more authors to the first author plus et al. from the very first citation, while the reference entry for the same work lists up to twenty names. Three in the text, twenty in the list, one style. Carry the in-text threshold into your bibliography, or the bibliography cutoff into your prose, and both are wrong.
So when a journal's spec says "first six authors, et al.," read it as a reference-list instruction and nothing more.
Why does your reference manager get this wrong?
Because a reference manager applies one output style to the whole document, and that style file encodes one cutoff. The journal you are submitting to may not be the journal the style file was built for.
Zotero, EndNote, and Mendeley all format from a style definition you select once. Pick a generic Vancouver style and you get whatever truncation its author chose. The failure is quiet: every entry looks tidy, the et al. lands where the style file says, and nothing warns you that the target journal wanted a different number. The danger concentrates after a rejection, when the manuscript moves to a new journal and the bibliography silently keeps the old journal's shape.
Two checks catch it. First, find the reference-list sentence in the new journal's guide for authors and read the number it states. Second, look only at the entries the cutoff can touch: references with seven or more authors under a six-author rule, four or more under a three-author rule. In most bibliographies that is a handful of entries, not hundreds. A review that checks each reference against the target journal's own rule set runs the same comparison automatically and quotes the journal's sentence next to the entry that breaks it, which beats re-deriving the rule from a style file's behavior.
The cutoff is small, mechanical, and entirely journal-specific. Six at PLOS ONE. Six plus a DOI at Frontiers in Neurology. Three under AMA, twenty under APA. Look it up per journal, per submission, every time.