Prompt set
The fixed list of questions your visibility is measured against. It is the denominator of every number anyone will show you, and it has to be written down before the work starts.
Checkable · the test is below
What it means
Simply the questions, agreed in advance: who is the best heating contractor in this town, who does emergency AC repair on a Saturday, what does a furnace replacement cost around here. Everything else hangs off it, and changing the list changes every number with it.
Why it matters for an HVAC company
A prompt set chosen after the fact is how a bad result becomes a good one. An agency free to pick the questions at reporting time will pick the ones you already win, and nothing dishonest has to be said for that to happen. Fixing the list at the start is the cheapest protection you have.
What would settle it
Ask for the list in writing at the start, then check every report covers the same list. If questions appear, disappear or get reworded between reports, the trend is not comparable and any percentage change in it is meaningless.
A worked example
Fifty questions across four services and three towns. March: named in 12. April: named in 19, same 50. That is comparable. The failure case is an April report also covering 50 questions where eleven are new and eleven are gone: the number looks the same and means nothing.