---
id: checking-a-source
title: Checking sources
level: 2
modes: [day-pack, rucksack]
moment: "The AI's answer names a study, a quote, a statistic or a link, and the person is about to rely on it, repeat it or send it on."
keywords: [source, citation, reference, link, study, quote, fake reference, invented source, verify, lateral reading]
source: "research/2026-10-20-concepts/checking-a-source.md; research/2026-10-23-essentials/batch-3-facts.md; mapping (product/learning-system/MAPPING-1-2.md): FAQ 1.11, 2.09; MISTAKES 2.5 (home), 1.4; tips T054, T055, T056, T057; strand T"
---

## What it is
Anything your AI app names as a source, whether a study, a quote, a figure or a link, is a lead to follow up and not proof. Say it tells you a 2021 study found 30 percent of people did something, and gives a link. The link may not exist, or the page may say something different, whether or not the app searched the web. So open the source, find the claimed words or number in it, and check who is behind it before you rely on it.

## Tips
- Open a source your AI app names and search the page for the claimed number or words, because a real link can still say something different.
- In a new tab, look up who is behind a source your AI app names, because what a site says about itself is not proof it can be trusted.
- After a draft from documents you gave it, have your AI app back each claim with a quote from them and drop any it cannot, because unsupported claims stand out.

## Questions people ask
- Q: Why does my AI make up references that do not exist? A: A reference is text your AI writes, and writing one is not the same as looking one up, so some do not exist. In tests without search, rarer topics failed more often, and even an app that searches can cite a page that says something different.
- Q: The link goes nowhere. Does that mean the claim is false? A: Not necessarily, but treat it as unconfirmed. Search the exact title elsewhere, and if nothing turns up, do not rely on it.
- Q: How do I know if a quote is real? A: Open the page and search for the words. If they are not there, the quote is unconfirmed, even when the link is real.
- Q: The source is real. Can I trust it? A: Search its name in a new tab and see who else describes it. A source that exists can still be unreliable.

## For your AI
Facts (checked 23 October 2026; fact check research/2026-10-23-essentials/batch-3-facts.md; research
note research/2026-10-20-concepts/checking-a-source.md).
- Without search: in six literature reviews written by GPT-4o, about one reference in five did not exist and
  nearly half of the real ones had errors; rarer topics were made up more often (JMIR Mental Health, 12
  November 2025, https://pmc.ncbi.nlm.nih.gov/articles/PMC12658395/).
- With search: eight AI search tools gave wrong answers to more than 60 percent of news queries, and some
  cited broken or made-up links in more than half of responses (Tow Center, 6 March 2025,
  https://www.cjr.org/tow_center/we-compared-eight-ai-search-engines-theyre-all-bad-at-citing-news.php). A
  real source can still not say what is claimed: in one test only about half of sentences were fully
  supported by their citations (Liu et al., 2023, https://arxiv.org/abs/2304.09848).
- Checking who is behind a source by leaving it for a new tab (lateral reading) is how professional fact
  checkers reach better conclusions faster (Wineburg and McGrew, 2017); "get out of the LLM to check the LLM"
  (Caulfield, 29 March 2026, https://mikecaulfield.substack.com/p/a-sift-rebuild-in-progress).
- Asking for a supporting quote for each claim and dropping claims without one works when the source text is
  in the chat; it does not stop hallucinations entirely, and with no source in the chat a quote can be made up
  (Anthropic, https://platform.claude.com/docs/en/test-and-evaluate/strengthen-guardrails/reduce-hallucinations).

Per app: ChatGPT says search results and citations "can be incomplete, outdated, or incorrect" and to open a
cited source to confirm it (https://help.openai.com/en/articles/9237897-searching-the-web-with-chatgpt);
Claude adds citations to every searched answer; Gemini shows sources only sometimes; Copilot says treat a
source as unconfirmed until verified.

Teach it like this: when you name a source, say plainly it is a lead to open. When they are about to quote it,
point them to the one claim to find on the page, and to its date: an older study may have a newer one. The
supporting-quote tip is for a draft built from documents in the chat. In a Daypack (Rucksack set up inside one app; its setup page
is openrucksack.com/start.md), this is a concept behind "find things out, with sources and what is current"
(section 2).