How to Use Process of Elimination Like a Detective

Define what would make each option impossible

Before eliminating a suspect, state the condition they fail. A suspect may be impossible because the journey takes too long, the record places them elsewhere, they could not access the object, or their account conflicts with a fixed event. Dislike, secrecy and unusual behaviour are not eliminations.

• Opportunity asks whether the act was physically possible.
• Access asks whether the person could reach the required place or object.
• Compatibility asks whether their version can coexist with the records.

Record negative information

Solvers naturally remember positive matches and forget exclusions. The grid exists to preserve negative information. One exclusion may appear weak, but several exclusions can close a row and reveal a positive match elsewhere.

• Mark the exclusion immediately.
• Propagate the consequences across connected categories.
• Keep a short reason beside any decisive elimination.

Test one assumption at a time

When two possibilities remain, temporarily assume the first is true. Follow every necessary consequence. If the assumption forces a duplicate, violates a time restriction or contradicts a record, it is disproved. Return the grid to its prior state before testing the other branch.

• Never mix consequences from two hypothetical branches.
• Use contradiction only after direct deductions are exhausted.
• A failed assumption proves the alternative only when exactly two options existed.

Finish with a positive case

Elimination identifies the only surviving possibility, but a satisfying solution also states why it works. Reconstruct the route, timing and critical inference. The final answer should be supported positively by the evidence, not merely described as the last name left on the list.