How to Fact-Check ChatGPT's Answers (and Spot Made-Up Facts)

The short version

ChatGPT sounds equally sure when it’s right and when it’s wrong. So check by type of claim, not by how confident it sounds. Specific facts get verified; general explanations usually just need a sense check.

What to check, from most to least risky

1. Quotes, citations and links: may be misquoted, invented or point somewhere else.
2. Numbers and statistics: prices, percentages, dates, measurements.
3. Laws, rules and medical facts: they differ by place and change over time.
4. Recent events: anything after the model’s training needs a source you can see.
5. Names and details of people, products and companies.
6. General explanations: usually fine, but still worth a sense check.

Step by step

1. Ask where it might be wrong (prompt below). It’s surprisingly good at flagging its own weak spots.
2. Ask for sources, then open every link. Check it exists and actually supports the claim.
3. Use web search for recent facts, so the answer cites pages you can open.
4. Go to the original source for anything that matters: the law itself, the company’s own pricing page, the study, the official statistics.
5. Cross-check numbers in a second place before you use them.

Prompts to copy

Flag the risky parts:

Which statements in your answer are you least sure about, and which should I verify before relying on them?
List them with what kind of source would confirm each.

Separate fact from guesswork:

Rewrite your answer and mark each claim as [VERIFIED FACT], [COMMON KNOWLEDGE] or [MY ESTIMATE].

Find original sources:

For each number in your answer, tell me the organization that would publish the original figure
and the name of the report or page I should look for.

Example

Asked for “the minimum wage in Colorado”, ChatGPT might give last year’s figure. The fix: check the state labor department’s own page, which lists the current rate and its effective date. One click, and you’re not relying on a figure that may have changed.

Mistakes to avoid

• Trusting confidence. Fluent and certain isn’t the same as correct.
• Not opening the links. A citation you haven’t checked is just more text.
• Using it as a search engine for live facts without seeing sources.

When it really matters

For health, legal, tax and money decisions, use ChatGPT to understand the topic and prepare questions, then confirm with a professional or the official source.

Related: how to use ChatGPT.