Watson–Glaser Inference guide
Watson–Glaser Inference gives you a passage of assumed-true facts and asks you to grade a proposed inference on a five-point scale — True, Probably True, Insufficient Data, Probably False, False — judged strictly from the passage.
The method
- Treat the passage as true and ask how strongly it supports the inference.
- Learn the five grades as bands of probability, and where their boundaries sit.
- Grade from the passage only — not from what you know about the world.
- Use Insufficient Data when the passage genuinely does not lean either way, not as a safe default.
Common mistakes
- Grading from world knowledge instead of the passage.
- Confusing 'Probably True' with 'True' on a directly stated fact.
- Defaulting to Insufficient Data whenever you feel unsure.
- Sliding one grade too strong or too weak on the scale.
Frequently asked questions
When is it True versus Probably True?
True is reserved for what the passage establishes beyond reasonable doubt; Probably True is the right grade when the passage makes it likely but not certain.