Checking AI content: is it true, and is it good evidence?
About 30 minutes · plain language
An AI answer is only as good as the data and sources behind it. If the data are wrong, old or one-sided, the answer will be too, however fluent it sounds. This lesson gives you a simple, evidence-based routine for checking anything AI tells you, or anything you read online, before you act on it or pass it on.
- Explain why an AI answer can only be as good as the data and sources behind it.
- Use a five-step routine to check any AI answer before you act on it or share it.
Key terms
- Garbage in, garbage out
- A computing saying: if the input data are wrong, the output will be wrong too.Example: A model trained on outdated drug guidance gives outdated doses.
- Training data
- The text or records an AI model learned from. They may contain errors, old information and bias.Example: Web pages, books and articles collected up to a certain date.
- Knowledge cut-off
- The date after which the model has no information, unless it searches the web.Example: A model trained to 2024 does not know a guideline updated in 2026.
- Retrieval (grounding)
- When an AI tool searches documents or the web and bases its answer on what it finds. It reduces, but does not remove, errors.Example: A chatbot that answers from your hospital’s policy files and shows the file it used.
- Primary source
- The original report of a study, law or guideline.Example: The published trial, not a news story about it.
- Secondary source
- A summary or interpretation of primary sources.Example: A review article, textbook chapter or AI summary.
- Lateral reading
- Checking a claim by leaving the page and seeing what other trusted sources say about it and about who wrote it.Example: Opening PubMed and the WHO website in new tabs to check a chatbot’s claim.
- Level of evidence
- How much a type of study can be trusted to answer a question, for example a systematic review of good trials usually ranks above a single study or an expert opinion.Example: A Cochrane review outranks one blog post by a famous doctor.
- Evidence-based practice (EBP)
- Combining the best available research evidence with clinical expertise and the patient’s values and preferences.Example: Choosing a wound dressing using a guideline, your assessment and what the patient can manage at home.
- Hallucination
- Content an AI tool makes up that sounds right but is false.Example: A reference with real authors but a title that does not exist.
Why AI answers can be wrong
A language model learned from a huge amount of text. Some of that text was wrong, out of date or biased, and the model cannot tell which. It also does not look facts up unless it is connected to a search tool. It writes the most likely answer. So an answer can be:
- Made up: invented facts, numbers or references (hallucinations).
- Out of date: based on information from before its knowledge cut-off.
- Biased or one-sided: repeating what is common in its data, not what is best supported.
- Right in general but wrong for your case: a correct adult dose given for a child.
Good data in does not guarantee a good answer, but poor data in almost guarantees a poor one.
Step 1: Stop and name the claim
Before you use or share anything, write the claim in one sentence. “Chlorhexidine bathing reduces bloodstream infections in ICU patients.” A clear claim is easier to check than a whole paragraph. Notice how the answer makes you feel: a confident tone or an answer you were hoping for are reasons to check more, not less.
Step 2: Ask where it came from
Does the AI show a source? Is it a primary source (the study, guideline or law) or a secondary one (a summary)? Is the tool searching current sources, or answering from memory with a cut-off date? An answer with no source is a starting point for your own search, not a fact.
Step 3: Find and read the original
Use lateral reading: open new tabs and check the claim in trusted places, such as PubMed, a national or WHO guideline, the drug formulary or your institution’s policy. Confirm that each reference exists, that it says what the AI claims, and that it is current. Do not check one AI against another AI; that only checks that they agree, not that they are right.
Step 4: Judge the evidence
Not all sources are equal. Ask:
- What type of evidence is it? Guidelines and systematic reviews are usually stronger than single studies, which are stronger than expert opinion or anecdotes.
- Is it good quality? Use the appraisal tools you learned in research methods, and the AI-specific guidelines in this library for studies of AI tools.
- Is it current, relevant and from a reliable author? Simple checklists such as CRAAP (Currency, Relevance, Authority, Accuracy, Purpose) help with web pages.
- How sure are the authors? Good guidelines and reviews rate the certainty of their evidence, often with GRADE, from high to very low. Guidelines themselves vary in quality; AGREE II is a tool for judging how well a guideline was made.
An evidence ladder for any health content
One way to put Step 4 into practice is to give each source a place on a ladder. A published tool for rating the content of health apps (EBCRT-mHealth) scores sources from 5 down to 1. The ladder below is our simplified version of it:
- Clinical guidelines (international, national, professional bodies): around 4.5 to 5
- Systematic reviews and meta-analyses: around 4
- Randomised trials, then other studies (cohort, case-control, cross-sectional, case reports): around 3.2 to 3.8
- Websites of trusted institutions, specialist-reviewed sites, laboratory research, textbooks and expert opinion: around 2 to 3.1
- News sites, Wikipedia and blogs: below 2. A source that is not about the topic at all scores 1
The ladder rates the source, not the claim. A strong source can still be misquoted, and an old guideline can be out of date, so always combine the ladder with Step 3 (does the source really say this?) and the date.
A note on language
AI tools learn from what has been written. Much less peer-reviewed health research is published in Arabic or Persian than in English, so answers in these languages may lean more on news sites and general web pages. This is a reason to check more, not to stop using your own language: ask the tool for its sources, and check high-stakes answers against the original guideline, which may be in English.
Step 5: Apply it to your patient and setting
Evidence-based practice has three parts: the best evidence, your clinical expertise, and the patient’s values and preferences. Even correct evidence may not fit this patient, this setting or local policy. The final decision, and the responsibility, stay with you.
When to check more, and when less
Match the effort to the stakes. A suggestion for a study timetable needs little checking. Anything about a patient, a dose, a diagnosis, a law, a statistic or a reference needs full checking. If you cannot verify it, do not use it, or say clearly that it is unverified.
Case: the infection-control claim
A nursing student asks a chatbot whether chlorhexidine bathing reduces bloodstream infections in ICU patients. The answer says yes and cites a 2019 trial. She (1) writes the claim in one sentence, (2) notes the chatbot gave one secondary-sounding reference, (3) searches PubMed and finds the reference title does not exist, but finds real trials and a systematic review on the topic, (4) reads the review’s conclusions and certainty ratings, and (5) checks her hospital’s infection-control policy, which already covers it. In her assignment she cites the review and the policy, not the chatbot, and records how she used AI.
Common mistakes
- Trusting an answer because it is confident or has references.
- Checking one AI with another AI.
- Citing the AI tool instead of the original source.
- Applying a general answer to a specific patient without judgement.
Check your understanding
1. Why can an AI tool give an out-of-date answer even if everything it learned was once correct?
Because it only knows information up to its knowledge cut-off, unless it searches current sources.
2. A second chatbot agrees with the first one. Is the claim now verified?
No. Agreement between AI tools does not show the claim is true. Check the original source.
3. Name the three parts of evidence-based practice.
The best available research evidence, clinical expertise, and the patient’s values and preferences.
4. Which needs more checking: an AI-suggested study timetable or an AI-suggested drug dose?
The drug dose, because an error could harm a patient.
Try it
- Take one AI answer from your work or study this week and run the five steps. How long did it take, and what did you find?
- Rate one web page or AI summary with the CRAAP checklist.
Remember
- An AI answer is only as good as the data and sources behind it.
- Rate the source on the evidence ladder, then check that it really supports the claim.
- Stop, source, original, strength, fit: check before you act or share.
- Cite the original evidence, not the AI, and keep the final decision yourself.
- Sackett DL, Rosenberg WM, Gray JA, Haynes RB, Richardson WS. Evidence based medicine: what it is and what it isn't. BMJ. 1996;312(7023):71-2. doi.org
- Raeesi A, Khajouei R, Ahmadian L. Evaluation of HIV/AIDS-related mobile health applications content using an evidence-based content rating tool. BMC Med Inform Decis Mak. 2021;21(1):135. doi.org
- Wineburg S, McGrew S. Lateral reading and the nature of expertise: reading less and learning more when evaluating digital information. Teachers College Record. 2019;121(11):1-40. doi.org
- Blakeslee S. The CRAAP test. LOEX Quarterly. 2004;31(3):4. commons.emich.edu
- World Health Organization. Ethics and governance of artificial intelligence for health: guidance on large multi-modal models. Geneva: WHO; 2024. www.who.int
- National Institute of Standards and Technology. Artificial Intelligence Risk Management Framework: Generative Artificial Intelligence Profile. NIST AI 600-1. Gaithersburg (MD): NIST; 2024. doi.org
- Miao F, Holmes W. Guidance for generative AI in education and research. Paris: UNESCO; 2023. doi.org
- Walters WH, Wilder EI. Fabrication and errors in the bibliographic citations generated by ChatGPT. Sci Rep. 2023;13(1):14045. pubmed.ncbi.nlm.nih.gov
- Guyatt GH, Oxman AD, Vist GE, et al. GRADE: an emerging consensus on rating quality of evidence and strength of recommendations. BMJ. 2008;336(7650):924-6. doi.org
- Brouwers MC, Kho ME, Browman GP, et al. AGREE II: advancing guideline development, reporting and evaluation in health care. CMAJ. 2010;182(18):E839-42. doi.org
Lesson text is our own plain-language summary of these sources; it is not endorsed by their authors. Check the original before relying on any detail.