You have read the sources, built the argument and polished the prose. Then you notice a footnote with no page number, a reference list entry missing its date, and two authors spelled three different ways. Referencing is where strong essays quietly lose marks — not because the ideas are weak, but because the details slipped. The good news is that most citation errors are predictable, which means they are fixable. Here is a checklist of the mistakes that come up again and again across three of the most common styles in UK universities, and how to correct them before submission.

Start with your department's version, not a random guide

This is the mistake underneath many others: treating "Harvard" as one fixed system. Harvard is a family of author–date styles, and every university — often every school within a university — publishes its own version. APA and OSCOLA are more standardised, but institutions still add house rules, such as whether you italicise case names or how you format module readings.

Before you write a single citation, find the official guidance on your module page or library site, and use that document as your only authority. If a website suggests something different, your department's guide wins. Save the PDF somewhere you can find it at 2am.

Harvard: the quiet, consistent errors

Harvard mistakes are rarely dramatic. They are small, repeated and easy to miss.

• Inconsistent formatting. Decide once whether you write (Smith, 2019) or (Smith 2019), then apply it everywhere. Mixed punctuation suggests the referencing was assembled in a hurry.
• Missing page numbers for direct quotes. A quotation always needs a page or paragraph locator: (Smith, 2019, p. 45). Paraphrases usually do not, but check your guide.
• et al. used too early. Many Harvard versions want all authors on first mention and et al. from the second or third. Follow your guide's rule rather than guessing.
• Websites without dates. If there is no date, use "no date" or "n.d." consistently and include an access date if your guide asks for one.
• Corporate authors muddled. If the publisher and the author are the same organisation, do not repeat it twice in the reference.

Read your reference list as a standalone document. Every entry should follow the same order of information: author, year, title, source, access details. Consistency matters more than any single formatting quirk.

OSCOLA: footnotes with rules of their own

OSCOLA is used mainly in law, and it trips up students who are used to author–date systems. Three habits cause most of the damage.

Forgetting pinpoints

A footnote to a case or article should point to the exact page or paragraph you rely on, not just the source as a whole. "Smith v Jones [2018] EWCA Civ 12" tells the reader the case; "[2018] EWCA Civ 12 [34]" tells them where to look.

Repeating full citations

After the first full footnote, OSCOLA expects a shortened form — for example, the author's surname and a cross-reference to the earlier note. If the very next footnote cites the same source, "Ibid" is acceptable, with a pinpoint if the page has changed. Capitalise it at the start of a footnote. Do not scatter "Ibid" across notes that are several sources apart.

Ignoring the hierarchy of sources

Cases, legislation, journal articles and books each have their own citation pattern. Blending them — putting a case name in italics, for instance, or omitting the neutral citation — signals unfamiliarity. Check one example of each source type in your guide and copy the structure carefully.

APA: dates, initials and the details people skip

APA 7th edition is common in psychology, education and the social sciences. Its rules are precise, which makes errors easy to spot.

• Initials, not first names. The reference list uses surnames and initials: Smith, J. A. Not "John Smith".
• Dates in the right place. In-text: (Smith, 2019). In the reference list the year goes in brackets after the author, followed by a full stop.
• Sentence case in titles. Capitalise only the first word of a title, the first word after a colon, and proper nouns. Journal names, by contrast, keep their capitalisation and are italicised.
• Missing DOIs. Where a DOI exists, include it as a full link. Drop "Retrieved from" unless your guide says otherwise.
• Mismatched in-text and list entries. Every citation needs a list entry, and every list entry needs at least one citation. Run both directions.

The mistakes that cross all three styles

Some errors appear whatever system you use.

1. Citing sources you have not read. If you only know a source through another author's summary, use a secondary citation and name both — or better, find the original.
2. Quoting without quotation marks. Paraphrasing too closely, with a citation but no quotation marks, still reads as plagiarism.
3. Copying reference list entries from a database without checking them. Export tools misread capitalisation, author order and dates. Verify each entry against the source.
4. Leaving the reference list until the end. Build it as you write. Reconstructing twenty entries from memory the night before a deadline invites errors.
5. Inconsistent italics. Book and journal titles are italicised in Harvard and APA; OSCOLA italicises case names and some titles but not legislation. Pick a rule and keep it.

A five-minute final pass

Before you submit, work through your essay once with referencing as the only focus. Check that every in-text citation has a matching reference list entry, and every entry is cited somewhere. Scan for missing page numbers on quotations, confirm the punctuation inside brackets, and make sure the reference list is alphabetical or in the order your style requires. Then read your footnotes aloud — clumsy footnotes are easier to hear than to see.

If a rule is genuinely unclear, ask your tutor or library referencing team rather than guessing. A short email now beats a remark about inconsistent referencing later. Get the details right, and your markers can focus on the argument you worked so hard to build.

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