How to Spot a Credible Source

By Bethan McGloin
Sep 07, 2023
8 min read

Whether you’re a proofreader, an academic editor, or someone who simply wants reliable information, learning how to spot a credible source is vital.

This guide explores everything you need to know:

What the three main types of sources are
What makes a source credible
Why it’s important to use credible sources
How to identify a credible source
How to evaluate online sources
What to do if you spot unreliable sources in a client’s writing

Types of Sources

There are many kinds of sources, but they generally fall into three categories: primary, secondary, and tertiary.

Primary Sources

A primary source is a piece of firsthand evidence or an account involving original research, thoughts, or opinions. Examples include:

Newspapers and magazines
Original research articles
Letters or diary entries
Photographs
Audio clips such as speeches or interviews
Censuses and statistics
Podcasts
Novels and poems

Secondary Sources

A secondary source is a second-hand piece of information or an account that analyzes, describes, or evaluates primary sources. Examples include:

Journal reviews
Textbooks
Documentaries
Blog posts

Tertiary Sources

Tertiary sources combine primary and secondary sources, providing an overview, index, or summary. Examples include:

Almanacs
Dictionaries
Encyclopedias
Bibliographies
Indexes

What Is a Credible Source?

While the specific definition of credibility can differ between institutions and subjects, generally speaking, a credible source is:

Presented objectively
Backed up by evidence
Written by a reputable author or authors

Why Is It Important to Use Credible Sources?

When authors rely on credible sources, they provide readers with accurate, trustworthy information. If a piece of writing contains even a single glaring error or an unreliable claim, readers may question the integrity of the information and stop reading.

For proofreaders and editors, credibility is especially important. Clients who are submitting work for publication or assessment need to ensure any claims made in their documents are backed by trustworthy evidence. Using credible sources helps build the overall strength of an argument and protects both the author’s and the publisher’s reputation.

How to Tell Whether a Source Is Credible

To check whether a source your client has cited is credible, you should ask yourself a number of questions:

Who is the author? Ideally, the author should be an authority on the subject area. That is, they should possess a related qualification or be known well within their professional field. And they will usually have a history of publishing similar work. If you can’t find relevant information about the author, view the source with skepticism.
Who is the intended audience? Academics or specialists in a given field will usually be the intended audience of a credible source. Sources aimed at a general audience may be fine, especially if they’re clearly cited, but a more suitable scholarly or industry source will usually be available.
Where is it from? The best sources are usually from scholarly publications. Academic journals, for instance, are peer-reviewed, meaning experts in the field have approved the articles within. By comparison, an article on a blog or a Wikipedia page may have been reviewed less rigorously. And articles on news sites or in newspapers may depend on how trustworthy the individual publication is.
When was it published? For certain topics, recent sources are usually better. In the sciences, for example, it’s best to focus on the most recent research available because this is likely to be up-to-date.
Does it provide supporting documentation? A reliable source will provide evidence to back up its claims. This documentation may consist of data in tables, graphs, or illustrations, especially for scientific research.
Does it cite its own sources? Reliable scholarly writing should cite its own sources. Does the article or book your client is using include a reference list, bibliography, or citations? If not, it may not be a suitable source for academic writing.
Is it free from bias? A source may be biased if the author, the publication, or other involved parties stand to benefit from the conclusions it draws. For example, if a company that manufactures plastic issues a report on the impact of plastic waste on the environment, the piece may not be reliable because the company has a vested interest in the results.

You can use a number of frameworks and guidelines to critically evaluate a source. The CRAAP (Currency, Relevance, Authority, Accuracy, and Purpose) test is a popular method.

These guidelines are context-dependent, so what determines the credibility of a source can vary depending on the subject. Often, a credible source is simply one that experts in that field would agree is valid. In an essay about Charles Dickens, for example, his works will be primary sources. And the reliability of Great Expectations as a source in this scenario is not undermined by the work’s lack of citations or its 1861 publication date.

However, when an author is citing a source not to discuss it directly but to back up a claim they’re making (e.g., citing a scientific paper to provide background for an experiment), then reliability is pertinent. And if a source doesn’t fit the criteria outlined above, it may not be reliable enough to cite in an academic paper. Should this situation arise while editing, you’ll need to flag the issue with your client.

How to Know Whether an Online Source Is Credible

Online sources are now common in academic writing, but they often lack clear publication dates and authors, and they may be subject to less rigorous review than print sources. As an editor, this situation can make it hard to determine whether your client has cited a credible web source.

Before you trust a website, ask:

Who produced the content? Is there a named author whose credentials you can verify? Is it published by an authoritative institution (e.g., a university, major publisher, or government organization)? If it’s anonymous, treat it with caution.
Does the site list or link to its sources? If not, see if you can find the same information presented elsewhere. The more reputable sources there are to confirm a claim, the better.
Is the site professional and up-to-date? If you’re looking up referencing formats, does it mention the latest edition of the relevant style guide? Are there noticeable errors on the site? Does it appear abandoned or poorly maintained? These are red flags.

While you won’t always be able to tell whether an online source is credible just by looking at its URL, the following domain extensions can give you some idea of how trustworthy a web source is:

.edu (academic institutions) – University and college websites are generally geared toward a scholarly audience. However, you should check that content is authoritative, up-to-date, and unbiased.
.org (charity or not-for-profit organizations) – Many of these sites will be informative, but they may be biased toward a certain agenda.
.gov/.gov.uk/etc. (government-run sites or resources) – While government sites are usually reliable and authoritative, they may be influenced by political bias.
.com/.co.uk/etc. (commercial sites, usually owned by a company) – Commercial sites can provide useful information, but they are not usually scholarly sources, so they should be used carefully. Keep in mind that many will have an explicit marketing or promotional purpose.

Wikipedia and User-Generated Content

Sites like Wikipedia are not the most reliable sources. The problem is that anyone can add to or edit the information there, so the data could be flawed or even completely incorrect.

As with other online sources, you should check whether:

The user has provided relevant sources to back up their information.
You can find the information reproduced elsewhere online.

You can use Wikipedia to get an overview or simplification of a topic. Information on a given topic can also include links to primary and/or secondary sources, which you can find at the bottom of the page. It’s possible to use Wikipedia, with caution, as a tertiary source.

The Role of the Editor

If you work as an editor, your job is to revise a document to ensure clarity, concision, and proper academic tone. For proofreaders, your main focus is typically on spelling, grammar, and consistency. While neither role typically includes full-scale fact-checking, you may want to note issues with source reliability if you suspect a problem.

Remember, though, that fact-checking isn’t part of proofreading, so this only applies to things you look up while working, such as consistency in spelling or names. You don’t need to check your client’s sources for them.

You should also be mindful of the guidelines for academic integrity. For example, if you’re proofreading a student’s paper, suggesting alternative sources or offering substantive commentary on their content may be considered academic plagiarism. Instead, you can flag potential issues with their references and advise them to review their sources. But you wouldn’t usually recommend a specific source to replace the questionable one, as that could overstep the boundaries of proofreading or copy editing.

Becoming A Proofreader and Editor

Understanding how to spot credible sources is essential for proofreaders and editors. By applying the guidelines provided above, you can help ensure that your clients’ work is supported by reliable information. If you’d like to learn more about editing and proofreading, try our Becoming A Proofreader and Becoming An Editor courses. You can even buy both courses together to save 15%.

Get started with some free lessons today!

Updated on March 26, 2025