APA vs MLA vs Chicago: Which Citation Style Keeps Similarity Lowest?

Could your choice of citation style really change your Turnitin score? Not directly — Turnitin doesn't grade your formatting. But sloppy or inconsistent citation is one of the most common hidden drivers of inflated similarity scores, and each style has its own traps.

This guide compares APA, MLA, and Chicago, shows where each one trips students up, and gives you formatting habits that keep your score clean regardless of style.

The Three Styles at a Glance

• APA (7th edition) — Author–date in-text citations: (Smith, 2020). Dominant in psychology, education, business, and the sciences. Reference list titled "References."
• MLA (9th edition) — Author–page in-text citations: (Smith 23). Standard in literature, languages, and the humanities. List titled "Works Cited."
• Chicago (17th edition) — Two systems: Notes & Bibliography (footnotes/endnotes, common in history) and Author–Date (like APA, used in sciences). List titled "Bibliography" or "References."

Does Citation Style Affect Your Similarity Score?

Indirectly — in three ways:

1. Reference list exclusion depends on formatting

Most institutions configure Turnitin to exclude the bibliography from scoring — but the software has to recognize it. A clearly headed, consistently formatted reference list ("References" / "Works Cited" / "Bibliography") gets excluded cleanly. A jumbled list with mixed styles may not be detected, and every entry then counts toward your percentage.

2. In-text citation errors create false matches

When you forget an in-text citation, a paraphrased passage looks uncredited — exactly what the algorithm is hunting. APA's author–date format makes missing citations easy to spot while proofreading; Chicago footnotes are easier to accidentally skip when you're tired.

3. Quotation formatting signals legitimacy

Properly formatted block quotes (indented, per your style guide) are instantly recognizable to instructors reviewing your report. A quote dumped inline with no formatting looks like copied text — because, visually, it is.

Style-Specific Traps to Avoid

APA traps

• Missing DOIs or URLs in references — incomplete entries look sloppy and may not be excluded properly.
• Forgetting the year in every in-text citation — (Smith) instead of (Smith, 2020) is an error that also weakens your credibility.
• Inconsistent ampersand use: (Smith & Jones, 2020) in parentheses, Smith and Jones (2020) in narrative.

MLA traps

• Omitting page numbers — (Smith) alone is incomplete in MLA and a red flag in reports.
• "Works Cited" entries without hanging indents — formatting chaos makes the exclusion filter less reliable.
• Mixing 8th and 9th edition rules (especially container formatting for online sources).

Chicago traps

• Footnote numbers that don't match the bibliography — the most common Chicago error, and it undermines the whole system.
• Mixing the two Chicago systems in one paper — pick Notes & Bibliography or Author–Date, never both.
• Shortened notes missing key details on repeat citations.

5 Formatting Habits That Lower Every Score

1. Pick one style and commit. Check your syllabus — when in doubt, ask. Consistency beats correctness debates.
2. Format the reference list first, not last. Building it as you write prevents the end-of-night citation scramble where most errors happen.
3. Cite as you paraphrase. Add the in-text citation the moment you write the sentence, not later. "Later" is where citations go to die.
4. Use a citation manager. Zotero and Mendeley are free and eliminate 90% of formatting errors automatically.
5. Proofread citations separately. Do one dedicated pass checking only citations against your reference list — every in-text citation must have a matching entry and vice versa.

Frequently Asked Questions

Which style gives the lowest Turnitin score?

None, inherently. A perfectly formatted paper in any style scores the same. The "best" style is the one your department requires, executed consistently.

Does Turnitin check my reference list?

It scans everything unless configured to exclude the bibliography. Reference entries match other papers' references constantly — which is why proper exclusion settings matter.

Can I mix citation styles?

Never in one paper. Mixed styles signal carelessness to instructors and confuse exclusion filters. One paper, one style, throughout.

Final Thoughts

Citation style won't save bad writing — but bad citation can sink good writing. Treat your references with the same care as your argument, and your similarity score will reflect your actual originality.

Want to verify your formatting is doing its job? TurnPro AI runs official Turnitin similarity and AI checks with non-repository protection — see your true score before your professor does.