Critical Thinking · Media Literacy
The F.A.S.T. System
Try to disprove the claim — and trust it more when you can't.
F.A.S.T. is a four-step fact-checking framework built around falsification rather than confirmation. Instead of gathering evidence in favor of a claim, you deliberately search for reasons it might be wrong. If you try hard to disprove something and can't find credible disconfirming evidence, that failure is itself good evidence for the claim. Once practiced, running through F.A.S.T. takes only a few minutes — and it's close to how professional fact-checkers actually work.
Download the Full Reading (PDF)F — Find the Original Source
Track down where the claim actually came from. For scientific claims, look for a peer-reviewed paper or official research institution press release. For news stories, find the original outlet that first reported it. For social media posts, trace the chain of attribution back as far as it goes. A credible source should get you to the primary material in two clicks or fewer.
If you're three or more clicks deep with no primary source in sight, that's a signal worth noting.
A — Assess the Original Source
For websites, use the Wikipedia trick: search the domain name with "wikipedia" appended and read what others say about it rather than reading the source itself — this is called lateral reading. For news outlets, distinguish between bias (political leaning) and agenda (what the organization is actually trying to accomplish). For scientific papers, verify author affiliations, a conflict of interest statement, a DOI, and journal citation information — all markers of a genuine peer-reviewed publication.
A low credibility score doesn't mean a particular story is false. It means you need more corroboration from better sources before accepting or sharing the claim.
S — Search for Disconfirming Information
Actively look for credible reasons the claim might be wrong. For scientific claims,
find the paper on Google Scholar and click "Cited by" to see responses, critiques,
and replication attempts. For factual claims, use the site: operator to
search fact-checking sites directly — e.g., site:snopes.com. Use
exact-phrase searching, date filtering, and the minus operator to get past irrelevant
results. Treat AI-generated search summaries with skepticism: they can omit contradicting
evidence and present contested claims with false confidence.
Searching for disconfirming evidence while secretly hoping you won't find any isn't using this framework. The system only works if you engage honestly with the claim.
T — Test Relevant Explanations
A claim often comes down to competing explanations for the same evidence. The final step is abductive reasoning — inference to the best explanation. Rather than trying to prove a claim true, weigh the competing explanations against one another and accept whichever best accounts for all the available evidence. A claim that survives that comparison has earned your confidence; one that holds up only by ignoring a better explanation has not.
The key question isn't just "is this well-sourced?" but also: "is this the best available explanation for what we observe?"
For Instructors
F.A.S.T. was developed for use in undergraduate critical thinking and media literacy courses. It is built around the logic of falsificationism and designed to be practical — students can work through the four steps on a real claim in a single class period. The full classroom reading (available above) includes worked examples, advanced search techniques, and a treatment of peer review and predatory journals. If you're interested in adopting or adapting the system for your own course, feel free to reach out: whalen@southalabama.edu