One of the most important steps in conducting research for a paper or project is finding and evaluating credible sources. Using unreliable sources can undermine the quality of your work and damage your credibility. But what makes a source “credible”?
Here’s a guide to understanding different types of sources and how to identify those you can trust.
Types of Sources
Primary sources provide first-hand, direct accounts or evidence about the subject or event being examined. As these originate from the source, they are considered highly credible for supporting arguments and claims. However, it’s important to critically evaluate primary sources to ensure their information is reliable and factual.
| Types | Definition | Examples |
| Primary Sources | First-hand accounts, direct evidence, or raw data originating from the source or event being studied | – Historical documents (letters, diaries, – Speeches or interviews – Photographs – Newspapers and magazines – Audio clips like speeches or interviews |
| Secondary Sources | Sources that analyze, interpret, evaluate, or build upon primary sources | – Books and textbook – Journal articles and essays – Commentaries and criticisms – Documentaries and biographies – Literature reviews |
| Tertiary Sources | Sources that compile and summarize primary and secondary sources to provide an overview or entry point | – Encyclopedias and Dictionaries – Handbooks and Guidebooks – Bibliographies and literature guides – Almanacs and fact books – Manuals and instructional materials |
How to Identify a Credible Source
No matter the type of source, there are some universal signs of credibility to look for:
- Author’s expertise – Check the author’s credentials, employment, background, and other published works. A relevant degree or experience in the subject area boosts their authority.
- Publisher – Credible books and journals typically come from a university press, academic association, government entity, or respected commercial publisher with editorial oversight.
- Objectivity – The source should aim to be balanced, minimally biased, and represent other viewpoints fairly. Inflammatory rhetoric is a red flag.
- Citations – The source should cite its own evidence from other credible, traceable sources rather than making unsupported claims.
- Currency – More recent sources are preferable for rapidly changing subjects. However, older sources can still be credible in some contexts.
The CRAAP Test
For quickly evaluating sources, especially websites, many experts recommend the “CRAAP test“:
- Currency – How recent is the information? Newer is better for most topics.
- Relevance – Does it relate directly to your research question or cover the right topic area?
- Authority – What are the author’s credentials and the publisher’s standards?
- Accuracy – Does it make claims without evidence? Check for citations.
- Purpose – Is it objective information or persuasive/biased?
The specific standards you use to assess each criterion will vary depending on your research topic’s subject matter and focus.
For instance, if you investigate the latest breakthroughs in a rapidly evolving scientific or technological field, source materials just a decade old may already be outdated and lacking in currentness. However, if your area of study centers on an ancient historical event like the Peloponnesian War, consulting sources from a few centuries ago would be appropriate and still highly relevant.
Where to Find Credible Sources
Credible sources are easy to find when you know where to look:
- University libraries – Access academic journals, books, and databases curated by subject experts.
- Google Scholar – Search for scholarly literature across disciplines.
- Government websites – Search .gov for reputable data, reports, and information.
- Academic associations – Professional associations often publish peer-reviewed research.
- Database subscriptions – Some academic databases require a paid subscription.
When searching online, credible sources generally end in .edu or .gov rather than .com or .org.
Evaluating Web Sources
Since anyone can publish on the web, it’s important to carefully evaluate online sources. Red flags include:
- Lack of authors – Credible sources list author names and credentials.
- Advertising/bias – Too much advertising or clear promotion of a product/ideology.
- Looking amateurish – Poor writing, design flaws, broken links.
- Private websites – Anyone can create their own website or blog without oversight.
Despite the wealth of information online, you should rely primarily on print sources or vetted websites from credible organizations. When in doubt, ask a librarian for guidance!