A credible source is free from bias and backed up with evidence. It is written by a trustworthy author or organization. There are a lot of sources out there, and it can be hard to tell what’s credible and what isn’t at first glance. Evaluating source credibility is an important information literacy skill. It ensures that you collect accurate information to back up the arguments you make and the conclusions you draw.

Types of sources

There are many different types of sources, which can be divided into three categories: primary sources, secondary sources, and tertiary sources. Primary sources are often considered the most credible in terms of providing evidence for your argument, as they give you direct evidence of what you are researching. However, it’s up to you to ensure the information they provide is reliable and accurate. You will likely use a combination of the three types over the course of your research process.

How to identify a credible source

There are a few criteria to look at right away when assessing a source. Together, these criteria form what is known as the CRAAP test.

The CRAAP test

The CRAAP test is a catchy acronym that will help you evaluate the credibility of a source you are thinking about using. California State University developed it in 2004 to help students remember best practices for evaluating content.

The criteria for evaluating each point depend on your research topic. For example, if you are researching cutting-edge scientific technology, a source from 10 years ago will not be sufficiently current. However, if you are researching the Peloponnesian War, a source from 200 years ago would be reasonable to refer to. Be careful when ascertaining purpose. It can be very unclear (often by design!) what a source’s motive is. For example, a journal article discussing the efficacy of a particular medication may seem credible, but if the publisher is the manufacturer of the medication, you can’t be sure that it is free from bias. As a rule of thumb, if a source is even passively trying to convince you to purchase something, it may not be credible.

Newspapers can be a great way to glean first-hand information about a historical event or situate your research topic within a broader context. However, the veracity and reliability of online news sources can vary enormously—be sure to pay careful attention to authority here. When evaluating academic journals or books published by university presses, it’s always a good rule of thumb to ensure they are peer-reviewed and published in a reputable journal.

What is peer review?

The peer review process evaluates submissions to academic journals. A panel of reviewers in the same subject area decide whether a submission should be accepted for publication based on a set of criteria. For this reason, academic journals are often considered among the most credible sources you can use in a research project– provided that the journal itself is trustworthy and well-regarded.

Where to find credible sources

What sources you use depend on the kind of research you are conducting. For preliminary research and getting to know a new topic, you could use a combination of primary, secondary, and tertiary sources.

As you dig deeper into your scholarly research, books and academic journals are usually your best bet. Academic journals are often a great place to find trustworthy and credible content, and are considered one of the most reliable sources you can use in academic writing.

Google Scholar is a search engine for academic sources. This is a great place to kick off your research. You can also consider using an academic database like LexisNexis or government open data to get started. Open Educational Resources, or OERs, are materials that have been licensed for “free use” in educational settings. Legitimate OERs can be a great resource. Be sure they have a Creative Commons license allowing them to be duplicated and shared, and meet the CRAAP test criteria, especially in the authority section. The OER Commons is a public digital library that is curated by librarians, and a solid place to start. 

Evaluating web sources

It can be especially challenging to verify the credibility of online sources. They often do not have single authors or publication dates, and their motivation can be more difficult to ascertain. Websites are not subject to the peer-review and editing process that academic journals or books go through, and can be published by anyone at any time. When evaluating the credibility of a website, look first at the URL. The domain extension can help you understand what type of website you’re dealing with.

In general, check for vague terms, buzzwords, or writing that is too emotive or subjective. Beware of grandiose claims, and critically analyze anything not cited or backed up by evidence.

Social media posts, blogs, and personal websites can be good resources for a situational analysis or grounding of your preliminary ideas, but exercise caution here. These highly personal and subjective sources are seldom reliable enough to stand on their own in your final research product. Similarly, Wikipedia is not considered a reliable source due to the fact that it can be edited by anyone at any time. However, it can be a good starting point for general information and finding other sources.