How to fact-check an AI answer without checking everything

Find the claims that matter, follow them to evidence, and separate what is supported from what is merely plausible.

A citation is a place to begin checking, not the check itself.

Find the claim that could change your decision

You rarely need to verify every adjective. Circle the statements that affect what you will do: a deadline, a price, a quoted policy, a compatibility claim, or a calculated total. An attractive weekend plan is not useful if its central attraction is closed. Check that first. This approach makes verification manageable and ties it to the actual consequence of an error.

Open the original material

Follow a citation to the source and find the relevant passage. Check who published it, when it applies, and whether it concerns the same place, product, or population. A real article can still fail to support the attached sentence. A page describing a pilot program in one city does not establish nationwide availability. If you cannot find the evidence, keep the claim unresolved.

Reproduce numbers outside the prose

For a simple total, add the inputs yourself. For a spreadsheet, inspect formulas and units. Suppose an answer says attendance doubled from 40 to 60: the increase is 20, which is 50% of 40, not 100%. Asking for the calculation can expose the mistake, but independently repeating it is the stronger check. Keep the source numbers beside the answer.

Use uncertainty to decide the next step

Label a claim supported, contradicted, or not established by the material available. “Not established” does not mean false. It means you need another source or should avoid relying on it. Two chatbots agreeing may reflect similar underlying material. If the decision has serious consequences, bring the relevant evidence to someone qualified to assess it.

A worked example

Original teaching example, not a recorded model run.

Vague starting point: Is all of this correct?

A more useful brief

List the three claims in this answer most likely to change my decision. For each, identify the source passage, date, and what remains uncertain. Do not treat the existence of a link as confirmation.

Why this helps: The request creates a checkable worklist. You still need to open the sources and assess the claims yourself.

Your turn

Try the source detective lab. For each claim, decide whether the supplied source supports it before revealing the explanation.

You are looking for this: You distinguish a false statement from a statement the source simply does not establish.

A quick check

A source covers one city. The answer says the program is available everywhere. What is the problem?

  1. The source may be real but does not support the broader claim
  2. Any citation makes the claim reliable
  3. The source must be fake

Answer: The source may be real but does not support the broader claim

The scope of the evidence must match the scope of the claim.

Sources and how to read this guide

Examples and exercises are original teaching material, not recorded model runs, measured time savings, or certifications. Official sources were consulted September 6, 2026. Product behavior can change.

Take the idea further

All learning paths | Practice challenges.

Related Power of AI pages

Keep reading with Start here, everyday uses, the tool guide, the writing workshop, and sources and standards.