How to tell if a source is credible: a checklist

To tell if a source is credible, leave the page before you judge it. Open a new tab, search for who is behind the source, see what other reliable outlets say about the claim, and trace quotes, numbers, and images back to where they first appeared. In research with professional fact checkers, the ones who used this habit, called lateral reading, reached better answers faster than historians and students who studied the page itself.

The short checklist

Use this list in order. Most sources take a few minutes.

Stop. Do you know this site or author? If not, do not read deeply or share it yet.
Investigate the source. Search the name of the site, organization, or author in a new tab. What do other people say about their expertise and their agenda?
Find better coverage. If you care about the claim more than this article, search for the claim itself. See what trusted outlets and experts say.
Trace the claim to the original. Follow the quote, statistic, study, or photo back to its first context. Check that it says what the page says it says.
Match the source type to the claim. A news story can report a study. The study itself is the evidence.
Check the date and status. Is it recent enough for the topic? Was it corrected or retracted?
Name the purpose. Is the page trying to inform you, sell to you, or persuade you?

Steps 1 to 4 are the SIFT method. Steps 5 to 7 cover what SIFT leaves to judgment. The sections below explain each part and the evidence behind it.

What lateral reading is, and why it works

In a study by Sam Wineburg and Sarah McGrew of the Stanford History Education Group, 45 people evaluated live websites: 10 professional fact checkers, 10 PhD historians, and 25 Stanford undergraduates. Stanford's summary of the study reports that the fact checkers were the fastest and most accurate group.

The difference was method, not intelligence. The fact checkers read laterally: after a quick scan, they left the site and opened other tabs to learn what others said about it. They also showed "click restraint," reading the search results before choosing what to open. The historians and students read vertically. They stayed on the original page and judged it by what it showed them. They were often misled by a professional-looking name and logo, an array of scholarly references, or a nonprofit URL. Wineburg put it plainly: "very intelligent people were bamboozled by the ruses."

The skill can be taught. In a later field study in high school government classes, published in the Journal of Educational Psychology, classrooms were randomly assigned, and students taught lateral reading grew significantly in their ability to judge the credibility of digital content.

SIFT: the four moves

Mike Caulfield describes SIFT in a 2019 post as four moves.

S: Stop. His rule: "Don't read it or share media until you know what it is." Stop has a second use. If you go down a rabbit hole while you check, stop and remember why you started.
I: Investigate the source. Caulfield writes that the expertise and agenda of a source are "crucial to your interpretation of what they say." He suggests "taking sixty seconds to figure out where media is from before reading."
F: Find better coverage. When the claim matters more than the article, "look for trusted reporting or analysis on the claim" and "scan multiple sources and see what the expert consensus seems to be."
T: Trace claims, quotes, and media to the original context. Screenshots, clipped quotes, and statistics lose their context as they spread. Find the first version and read it.

SIFT is fast because you do not need to read the original page well. You need to know what it is.

What about the CRAAP test?

The CRAAP test comes from Meriam Library at California State University, Chico. It asks questions under five headings: Currency, Relevance, Authority, Accuracy, and Purpose. The handout says that "different criteria will be more or less important depending on your situation or need."

The criticism is about where you look. Most CRAAP questions ask you to judge a page with what the page offers you: its stated author, its tone, its references, even its URL ending, such as .com, .edu, or .org. That is vertical reading, and the Stanford study shows how it fails. A nonprofit URL and a list of scholarly references fooled smart readers. A 2024 chapter by Mary Kamela, "Cut the CRAAP: Replacing vertical evaluation with lateral reading," makes this case and recommends lateral reading in its place. The Stanford group tested lateral reading in controlled studies. We did not find a comparable controlled test of the CRAAP checklist.

The CRAAP questions are still a good list of what to look for. Use them after you read laterally, not instead of it. Currency and Purpose in particular are worth a second look.

Know the source type

The type of source tells you what kind of evidence you hold. It does not tell you if the source is right.

Type	What it is	Examples
Primary	Direct or firsthand evidence	Original research articles, interviews, speeches, archival materials
Secondary	Interprets, analyzes, or reviews primary sources	Articles that review earlier research, most nonfiction books
Scholarly	By researchers for an academic audience, with full citations	Articles in JAMA or Nature
Popular	By journalists or staff writers for the public; usually short, rarely cites sources	Newspapers, magazines

The University of Central Florida library guide uses these definitions. Two points follow from them. First, a popular article that reports a study is a lead to the study, not a replacement for it. Second, "peer-reviewed" is not a guarantee. A Cochrane review found little empirical evidence that editorial peer review ensures the quality of biomedical research, though its authors stress that absence of evidence is not evidence of absence. Treat peer review as one good signal among several.

Signals of a credible source

The author or organization is named, and you can confirm their expertise somewhere else.
It cites primary sources, and the links work and say what the page claims.
It shows its methods and data, or explains how it knows what it says.
It separates news from opinion and labels sponsored content.
It posts corrections when it gets something wrong.
Other reliable sources cite it, or report the same facts on their own.

Red flags

You cannot find out who runs the site or who wrote the piece.
The claim appears nowhere else that you trust.
A quote, statistic, or image has no traceable origin.
The page sells a product, or earns affiliate money, tied to the claim it makes.
The tone is urgent or angry, and it asks you to share before you think.
The references look scholarly but do not support the claim when you open them.
The study was retracted. Check the Retraction Watch database, which Crossref acquired and made public in 2023.
The source is old and the topic moves fast.

Where Gregator fits

Gregator, which is our product, can give you a first map of the evidence when you learn a whole topic and cannot read laterally on every source. Every source it uses is classified by an AI model by type (peer-reviewed, institutional, journalism, or community) and for evidence quality, and each course shows a trust overview with the mix of source types and an evidence-quality label. Each Chapter shows its source count and peer-reviewed count, and inline footnotes let you open each source. Gregator does not show a score for each source, and it does not fact-check claims. Use the overview as a first read of the mix, then run SIFT on the footnotes behind the claims you plan to rely on.

Frequently asked questions

What is the fastest way to check if a website is reliable?

Open a new tab and search for the site or organization by name. Read what independent sources say about who runs it and why. This is lateral reading, and fact checkers used it to reach better conclusions in less time.

Is a .org or .edu website always credible?

No. A URL ending says little about quality. In the Stanford study, a nonprofit URL was one of the cues that misled historians and students.

Is the CRAAP test still useful?

Yes, as a list of questions. Its weakness is that it asks you to judge a page from the page itself. Do lateral reading first, then use the CRAAP questions on what you find.

Are peer-reviewed sources always credible?

No. Peer review is a useful signal, but evidence that it ensures quality is limited. Check the study design, its limitations, and whether it was retracted.

How do I check a statistic I saw on social media?

Trace it. Search for the number with a few keywords, find the first report or dataset, and check the date, the definition, and the context.