Why and when to cite
Citation gives credit, lets readers find your sources, and shows the conversation your work joins. Knowing when to cite is the first step.
Why we cite
Citation credits the people whose words and ideas you use, lets readers locate and check your sources, shows the research behind your argument (building ethos), and distinguishes your contribution from others'. Academic integrity policies treat failing to cite as a serious offence.
What needs citing
Cite direct quotations, paraphrases, summaries, statistics, data, images, charts, and any specific idea or finding that came from a source. Cite even if you found the source online, even if it is uncopyrighted, and even if you changed the wording.
Common knowledge
Common knowledge, facts widely known and easily found in many general sources, does not need citation: 'Paris is the capital of France' or 'World War II ended in 1945'. What counts as common knowledge depends on your audience and field. When in doubt, cite.
Citation styles
Different fields use different citation styles. MLA (Modern Language Association) is common in literature and humanities; APA (American Psychological Association) in psychology, education, and social sciences; Chicago in history and some humanities. Science fields often use styles like IEEE, CSE, or AMA. Follow your instructor's or publisher's requirements.
In-text and reference list
Most styles have two parts: brief in-text citations at the point of use, and a full list of sources at the end (MLA calls it Works Cited; APA calls it References; Chicago uses a Bibliography with notes). In-text citations point readers to full entries.
Current editions
Styles are updated periodically. Current editions are the MLA Handbook, 9th edition (2021); the Publication Manual of the APA, 7th edition (2019); and The Chicago Manual of Style, 18th edition (2024). Check which edition your course uses, as details change between editions.
Citing AI tools
Major style guides have published guidance on citing generative AI tools when their use is permitted. Typically you describe how you used the tool and cite the tool's creator, name, version, and date. Many institutions require disclosing any AI assistance; check your course policy first.
Worked example
A student writes: 'Teenagers' biological sleep cycles shift later during adolescence, so early school start times leave many chronically sleep-deprived.' The first part is a research finding, so it needs a citation. 'Many schools start before 8 a.m.' also needs a source unless it is common knowledge for the audience. The student's argument that start times should change is her own and needs no citation.
Key takeaways
Citation credits sources, helps readers find them, and builds credibility. Cite quotations, paraphrases, summaries, data, and specific ideas. Common knowledge needs no citation; when in doubt, cite. MLA, APA, and Chicago are the main styles, with current editions from 2021, 2019, and 2024. Styles pair in-text citations with a full list. Follow guidance and policy for citing AI tools.
Flashcard
Credit, findability, credibility
Check your understanding
Which of these does NOT normally need a citation?