How Watson Glaser deduction questions work
Each set gives you two or more statements and several conclusions. You accept the statements as true, even if they are false in the real world, and decide whether each conclusion follows necessarily from them.
Follows means there is no way the statements could be true and the conclusion false. If you can picture even one situation that fits the statements but breaks the conclusion, it does not follow.
This is stricter than Interpretation, where a conclusion only has to follow beyond reasonable doubt.
How to check whether a conclusion follows
Use the same routine for every conclusion:
- Restate each statement in its plainest form, such as “all A are B” or “some B are C”.
- Picture the groups as circles: inside one another, overlapping, or apart.
- Try to draw a version that fits every statement but makes the conclusion false.
- If you can, the conclusion does not follow. If no such version exists, it follows.
Worked example
Statements: “All the museum’s guides are trained in first aid. Some people trained in first aid work in the museum café.”
- “Some guides work in the café.” Does Not Follow. The first-aiders in the café could all be people who are not guides.
- “Anyone at the museum who is not trained in first aid is not a guide.” Follows. Every guide is trained, so someone untrained cannot be a guide.
- “Everyone who works in the café is trained in first aid.” Does Not Follow. The statements say some first-aiders work there, not that every café worker is one.
Tips for the real deduction questions
- Never reverse an “all” statement. “All auditors are accountants” does not make every accountant an auditor.
- In logic, “some” means at least one, and possibly all.
- The opposite of “every client paid” is “at least one client did not pay”, not “no client paid”.
- Ignore how true a conclusion sounds. A sensible conclusion can fail to follow, and an odd-sounding one can follow.
Practise Deduction on CogniPrep
Each run of our Deduction game is 12 sets of premises and a conclusion, drawn from a pool of 24, with 50 seconds per question and no going back. Running out of time counts as a wrong answer. The score out of 100 weights accuracy most, then pace, how evenly you handle Follows and Does Not Follow items, and how reliably you spot conclusions that do not follow. The per-question clock is ours; Pearson publishes only a time for the whole test.