30 January 2026
Citation Mistakes That Cost You Marks (And How to Fix Them)
Referencing errors are among the most preventable mark losses in university assessment. Here are the mistakes markers see most often, and exactly how to avoid them.
Referencing occupies a strange position in student awareness. Everyone knows it matters. Most find it tedious. And a significant number treat it as something to sort out in the final hour before submission, once the actual writing is done.
This is expensive. In most universities, referencing quality is assessed either as its own criterion or as part of a broader "academic conventions" section. A reference list with systematic errors can cost anywhere from two to eight marks depending on the rubric, which is often the difference between grade boundaries. The errors themselves are fixable. They require attention, not ability.
Harvard: The Most Common Mistakes
Harvard referencing (author-date) is standard across a wide range of UK and Australian universities, and widely used in US social science and humanities programmes. The errors I see most often are consistent enough to be worth naming directly.
Author formatting in the reference list should be surname first, then initials: Smith, J., not "John Smith," not "J Smith," not "Smith J." Apply this consistently throughout. Inconsistency signals that the reference list was assembled carelessly, possibly pulled from multiple sources with different conventions.
When you quote directly, the in-text citation must include a page number: (Smith, 2019: 45). Omitting it is one of the most common errors in student essays, and markers pick it up routinely. Students sometimes try to use "ibid" to avoid repeating a citation. Ibid belongs to the footnote tradition, Oxford and OSCOLA style. In Harvard work, just repeat the citation.
Your reference list should be alphabetical by first author's surname. Markers notice when it isn't, particularly when moderating work. For online sources, include an accessed date. Web content can change or disappear, which is why Harvard requires it, and many students leave it out entirely.
APA: Where the 7th Edition Trips Students Up
APA 7th edition changed several things from the 6th: the publisher location is no longer required for books; up to twenty authors are listed before an ellipsis replaces the rest; and the "Running head" label was removed from student papers. Mixing rules from both editions is extremely common, and it creates inconsistencies that markers notice.
DOIs in APA 7th should be presented as hyperlinks: https://doi.org/xxxxx, not just the raw number. If a DOI is available for a source, include it.
Capitalisation in article and book titles catches many students out. In APA reference lists, only the first word of a title, the first word after a colon, and proper nouns are capitalised: "The cognitive development of adolescents," not "The Cognitive Development of Adolescents." Journal names are title-cased, which is different. Applying journal rules to article titles is a mistake I see constantly.
For in-text citations with two authors, the format is (Smith & Jones, 2020), with an ampersand inside the brackets and "and" when written out in the sentence. For three or more authors, APA 7th uses et al. from the first citation onward. Alternating between formats, or applying et al. inconsistently, creates exactly the kind of friction that undermines a reference list's credibility.
The Mismatch Problem
One of the most consequential referencing errors is a mismatch between in-text citations and the reference list. Every source cited in the text should appear in the list. Every source in the list should be cited in the text. Running a check, going through your in-text citations and ticking them off against the reference list, takes fifteen minutes and eliminates one of the most common problems in student work. It's tedious. But it's fifteen minutes that might be worth a grade boundary.
A Note on Reusing Sources
If you've used a source in a previous essay, don't assume you remember the exact details accurately. Recheck the full reference each time. Publication details, including editions, page numbers, and DOIs, can vary between versions, and errors copied from old work have a way of becoming persistent habits.
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