Before we start writing notes and bibliography entries, let's step back and talk about why we cite sources in the first place, and what actually needs a citation.
Why we cite
When you write a paper, you're doing more than sharing your opinion. You're making an argument, and like any good argument, it needs evidence.
Citing your sources shows that your ideas are supported by research. In Turabian, a reader who wants to check a fact can glance down to the footnote on the same page, then find the full entry in your bibliography. That's how academic writing works: someone proposes an idea, others review the evidence, and the idea either holds up or it doesn't.
It's also exactly what your professor does when grading your paper. You put forward a thesis, support it with research, and are evaluated on how well you build your case.
What happens if you don't cite?
When you use someone else's idea without giving them credit, even by accident, it's called plagiarism.
Plagiarism is a big deal in academic settings. Whether you meant to do it or not, failing to cite your sources can have serious consequences. The good news is that it's easy to avoid. Stay organized and cite any ideas, words, or visuals that aren't your own, and you'll be in the clear.
What should you cite?
Here's a simple rule: if it isn't your original idea or a widely known fact, you should probably cite it. That includes:
- Direct quotes
- Paraphrased or summarized ideas
- Data or statistics
- Images, charts, maps, or graphs you didn't create
Basically, if it came from another source and it shaped your thinking or your paper, give credit where it's due.
Citing other people's work doesn't weaken your paper. It strengthens it, because it shows you've done your research and are building on the work of others. Even if your whole idea is a new combination of things other people have said, that's still original, and worth sharing.
What it looks like in a paper
Here is a passage from the sample Bigfoot paper with each borrowed piece marked. Every one of them gets a note.
Hair offered as proof of Bigfoot keeps matching animals we already know.1 Sykes and his colleagues tested 30 hairs credited to Bigfoot and similar creatures, and every hair attributed to Bigfoot matched an animal already known to science.2 A separate study reached a similar conclusion: “we nonetheless suspect that many Bigfoot sightings are, in fact, of black bears.”3
1. Bryan C. Sykes et al., “Genetic Analysis of Hair Samples Attributed to Yeti, Bigfoot and Other Anomalous Primates,” Proceedings of the Royal Society B: Biological Sciences 281, no. 1789 (2014): 20140161, https://doi.org/10.1098/rspb.2014.0161.
2. Sykes et al., “Genetic Analysis.”
3. J. D. Lozier, P. Aniello, and M. J. Hickerson, “Predicting the Distribution of Sasquatch in Western North America: Anything Goes with Ecological Niche Modelling,” Journal of Biogeography 36, no. 9 (2009): 1626, https://doi.org/10.1111/j.1365-2699.2009.02152.x.
- A paraphrased idea (note 1)The finding is in the writer's own words, so it still gets a note. The first note for a source is the full note.
- Data and statistics (note 2)The numbers come from the same study. The second note for a source is shortened.
- A direct quote (note 3)The exact words go in quotation marks, and the note gives the page they came from.
The footnotes lesson covers full and shortened notes in detail.
Quick checklist
- Every quote has a note with its page number
- Every paraphrase and summary has a note
- Every number, statistic, or image from a source has a note
- Your own conclusions and widely known facts need none
How PERRLA helps you cite
The hard part of citing is often keeping track of where things came from. With PERRLA's extension for Chrome and Edge, Add to PERRLA saves a source to your library from 85+ research databases, and a right-click saves a quote with it. When you write, each one is ready to cite: type # and pick it.