Reduce hallucinations in RAG by making the right evidence available, retrieving it correctly, and checking whether the answer stays within that evidence. Retrieval helps supply context; it does not guarantee factual accuracy.
Diagnose the failure stage
- Check whether the collection contains a correct, current answer.
- Verify the user is authorized to access that evidence.
- Inspect retrieved and discarded passages with their document versions.
- Check every material answer claim against the selected evidence.
- Test whether the application abstains when relevant evidence is missing.
Example: a missing policy exception
A policy document says ordinary returns are allowed, but a separate exception covers personalized items. An answer that cites only the ordinary policy can mislead. Add test questions that require the exception and check retrieval coverage before editing the prompt.
Keep measurement task-specific
Label unsupported claims and answer-level failures separately. Report the reviewed sample, scoring rubric, and false-positive rate of any automated checker. There is no universal acceptable hallucination rate for healthcare, legal work, or general RAG.
Keep source text untrusted
A retrieved document can contain adversarial instructions. Source filtering and factual grounding do not replace tool permissions or action confirmation. Test both correctness and the application’s authorization boundary.
References and further reading
Maintained by DriftRail. AI assisted the October 2026 content and template revision. Examples are illustrative; they are not measured product benchmarks. Suggest a correction.