Citation rate
The share of runs in which an engine names or links your business. Appearances divided by attempts, and the denominator is the part people leave out.
Checkable · the test is below
What it means
You ask an engine a question. Sometimes your company is in the answer and sometimes it is not. Citation rate is how often it is, across a set of questions fixed in advance and run a known number of times. A fraction needs both numbers to mean anything, so a citation without a denominator is a screenshot rather than a measurement.
Why it matters for an HVAC company
Because these systems are non-deterministic, being named once is close to meaningless. A homeowner asks once and which names they see is partly chance. Your citation rate is your share of that chance, and it is the honest thing to ask a vendor for, because a rate can go down and a screenshot cannot.
What would settle it
Fix a prompt set. Run each prompt several times per period, logged out, from the market you serve, against each engine named individually. Record every answer verbatim with its date. Count the runs naming you, divide by total runs, report both numbers and the period. Keep named and linked separate, and never narrow the question list between reports.
A worked example
A contractor runs 50 questions across four engines, three times each in one week: 600 runs. Named in 144, so 24%. By engine that is 41% on Perplexity, 28% on ChatGPT, 19% on Google AI Overviews and 8% on Gemini. The following month, same 50 questions, 29%.
The limit on that
The direction is real. The cause is not established, because a model update in the same month produces a similar-looking change with nobody having touched anything.