A claim is a flag somebody plants in the ground. Your job is to check what is holding it up — the evidence, the reasoning, and whether the source has earned your trust.
🚩What Is Holding This Claim Up?
CER: Claim + Evidence + Reasoning — a framework from education researchers Katherine McNeill and Joseph Krajcik.
🚩 Claim
A statement someone wants you to accept as true. Ads, science, and arguments all start with one.
🧱 Evidence
The facts, observations, or test results that support — or sink — the claim.
🧰 Reasoning
The mortar. It explains why the evidence actually supports the claim.
🪜Evidence Comes in Strength Levels
Always ask: is this one story, a pile of measurements, or a real test? One story can't rule out luck, extra practice, or a naturally fast cousin.
⚖️Fact or Opinion?
📏FACT
A statement that can be checked and proven true or false — settle it with a ruler, a stopwatch, or a measurement.
“This backpack holds 20 liters.” “This gum kept its flavor for 12 minutes in our stopwatch test.”
💭OPINION
Personal taste or belief that cannot be proven true or false. No experiment on Earth could end the argument.
“This backpack is the coolest.” “Mint is the most refreshing gum flavor.”
⚠️Watch out: ads love to dress opinions up in fact costumes. Sharp thinkers always ask which one they are looking at.
🕵️How Fact-Checkers Beat the PhDs
Stanford researchers Sam Wineburg and Sarah McGrew watched 10 historians with PhDs, 25 Stanford students, and 10 professional fact-checkers judge unfamiliar websites. The fact-checkers won — by reading LESS of each page, not more.
💡Why it works: a website will always tell you it is trustworthy. Only independent sources reveal a source's real credibility — its track record of expertise and honesty.
🔎The 4 SIFT Moves
S
Stop
Pause before you believe or share — especially if it makes you excited or angry.
I
Investigate the source
Take 30 seconds: who is behind this, and what do they want from you?
F
Find better coverage
Search what stronger, independent sources say about the same claim.
T
Trace to the original
Follow quotes, photos, and videos upstream — clips get trimmed until they seem to say something else.
Four moves from digital-literacy researcher Mike Caulfield.
🕶️Skeptic, Not Cynic
🧐SKEPTIC
Asks “how do we know?” — and genuinely changes their mind when good evidence arrives.
Trust should be earned by evidence, not granted by reputation alone.
😒CYNIC
Sneers that everything is a lie, so nothing ever gets checked.
Cynicism is just gullibility wearing sunglasses — a cynic is as easy to fool as a believer.
🐙The Octopus That Fooled a Classroom
In 2006, twenty-five seventh graders in Connecticut researched the “Pacific Northwest tree octopus” — a rare octopus said to slither between misty branches in Washington State, dodging its predator, the sasquatch. The site had photos, a habitat map, even tips for saving the species. Nearly every student rated it trustworthy. It is not real. When researcher Donald Leu revealed the hoax, many students refused to believe him — they weren't careless readers, they were untrained.
🍝Wait, Really?
📺On April 1, 1957, the BBC aired a report showing Swiss farmers “harvesting” spaghetti from trees — and hundreds of viewers called in asking how to grow their own spaghetti tree. Even a respected source can be wrong.
🏆In the Stanford study, every single professional fact-checker correctly judged which websites were trustworthy — while most PhD historians and Stanford students were fooled.
🌍Where This Shows Up in Real Life
🔬 Product testing labs
Groups like Consumer Reports buy products with their own money and run controlled side-by-side tests — the strongest kind of evidence — instead of trusting the ads.
📰 Newsroom fact-checking desks
Before a story runs, fact-checkers trace quotes, photos, and statistics back to their original sources — the same SIFT moves — because one unchecked claim can wreck an outlet's credibility.
🔑Key Terms
🚩ClaimA statement that someone wants you to accept as true.
🧱EvidenceThe facts, observations, or test results that support (or sink) a claim.
🧰ReasoningThe thinking that explains why your evidence actually supports your claim.
🗣️AnecdoteA single personal story used as evidence — like waving one puzzle piece and claiming you see the whole picture.
📊DataInformation, usually numbers, collected from many observations or measurements.
🌊SourceThe person, organization, or place information originally comes from — trace the river to its spring.
🛡️SkepticismThe healthy habit of asking for evidence before accepting a claim — a friendly bouncer at the door of your brain.
🔋CredibilityHow much a source deserves your trust, based on expertise, honesty, and track record.
⭐
A claim is only as strong as the evidence behind it and the reasoning that connects them — that's CER.
Evidence has strength levels: one anecdote is weakest, collected data is stronger, a controlled experiment is the gold standard.
Meet an unfamiliar source? Read laterally — leave the page, open tabs, check independent sources. That's how the pros avoid getting fooled.
A good question beats a fast answer. Stop. Then start asking.