ToolkitWeigh evidence
Evaluating a Source
Also called SIFT · Lateral reading · Source checking
Checking who is behind a claim and what others say about it before you trust or share it.
Purpose
Evaluating a source means finding out who is behind a claim, and what independent sources say about it, before deciding how much to trust it.
The instinct is to read a page closely and judge it by how it looks: the design, the tone, the “About” page. Research by Sam Wineburg and Sarah McGrew at Stanford found that professional fact-checkers do something different. They leave the page almost immediately and check what other sources say about it. They call this lateral reading, and it’s faster and more accurate than reading closely. The steps below follow Mike Caulfield’s widely used four-step method, known as SIFT.
When to use it
A claim surprises you, angers you, or confirms exactly what you hoped, which are the moments you’re least likely to check.
You’re about to share something.
A source you don’t recognize is presented as an authority.
A screenshot, quote, or chart appears without a link to where it came from.
A decision you’re making depends on the claim being true.
Steps
1Stop
Before reading further or sharing, pause and ask what you already know about this source and claim. Strong emotions are a cue to slow down, not speed up. This step takes seconds and prevents most mistakes.
2Investigate the source
Open a new tab and search for the source’s name, not the claim. Read what independent sites say about who runs it, who funds it, and what its track record is. A slick site with an “institute” in its name might be a lobbying group; a plain-looking page might be a respected expert. This is lateral reading, and it usually takes under a minute.
3Find better coverage
Search for the claim itself and see who else is reporting it. If reliable outlets or experts are covering it, you can rely on them instead of the original source. If only one source has it, or every report traces back to the same one, be cautious.
4Trace claims to the original
Quotes, statistics, and charts often get distorted as they’re shared. Follow them back to where they started: the original study, the full speech, the actual dataset. Check whether the context changes the meaning, and whether the number says what the post claims.
Worked example
A friend shares a screenshot of a chart titled “Crime in our city has doubled,” with a website’s logo in the corner.
Stop: It’s alarming, and it confirms what some people already fear. That’s a reason to check.
Investigate the source: A search for the website’s name shows it’s a new site with no listed staff, run by an advocacy group. That doesn’t make the chart false, but it means relying on the site alone isn’t enough.
Find better coverage: Local news outlets and the police department’s own reports show a rise in one category, car break-ins, over the past year. Overall crime rose slightly.
Trace to the original: The police data shows the “doubling” refers only to car break-ins, measured from an unusually low month. The chart dropped the label and cherry-picked the starting point.
Result: there’s a real increase worth discussing, but not the one the chart claims. The whole check took about five minutes.
Common mistakes
Judging a source by its design, domain name, or “About” page, all of which are easy to fake. A “.org” address says nothing about reliability.
Reading the source closely instead of checking what others say about it.
Treating sources as all good or all bad. Reliable outlets make mistakes, and unreliable ones are sometimes right; check the specific claim.
Mistaking many shares for many sources. Ten articles repeating one press release are one source.
Checking only the claims you doubt, and waving through the ones you agree with.
Sources & further reading
- Sam Wineburg and Sarah McGrew, “Lateral Reading and the Nature of Expertise: Reading Less and Learning More When Evaluating Digital Information,” Teachers College Record 121, no. 11 (2019): 1–40.
- Mike Caulfield and Sam Wineburg, Verified: How to Think Straight, Get Duped Less, and Make Better Decisions about What to Believe Online (University of Chicago Press, 2023).
- Mike Caulfield, Web Literacy for Student Fact-Checkers (2017). The original source of the SIFT approach’s core moves.
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