Why is a negative finding sometimes as informative as a positive one?

Diagnosis proceeds by elimination as much as by discovery. When an inspector finds a stain on a ceiling, the possible sources are a roof leak, a plumbing leak, a condensation problem or a past event already repaired, and each carries a different recommendation and cost. Establishing that the roof above is sound, that the attic is dry, and that the stain does not respond to moisture measurement removes possibilities and points the remaining evidence at a specific cause. Recording those negatives in the report is what makes the reasoning legible to the client and to whoever does the follow-up work — the plumber does not have to re-establish that the roof is fine. A negative finding also documents that the area was examined, which distinguishes 'checked and found sound' from 'not examined', a distinction that matters considerably after closing.

Eliminating a possible cause narrows the remaining explanations, which is how a diagnosis is built, and it documents that the area was examined rather than skipped.

Inspection reasoning proceeds by narrowing possible causes. Documented negative findings both support the diagnosis and establish that an area was examined rather than omitted.

Ruling Out Is Finding Out. Each cause you eliminate points harder at the one that is left.

Distinguish a documented negative from an unexamined area. 'Roof examined, no leak evidence' and 'roof not accessible' are very different statements.

• •Recording only defects and omitting what was checked and sound
• •Blurring 'found sound' with 'not examined'
• •Not carrying the eliminated causes into the recommendation