The rule is one line. Appraise two vehicles for every one you sell. Dealers who hold that ratio capture at least 53% of the trades that come through, against a franchise average around 34%.
The numbers to run the store against
- Capture rate: 50 to 60%. Under 40 and you are leaving units on the table that walked in on their own.
- Mis-trades: under 7 to 10%. A mis-trade is a car you appraised and lost. Some of that is unavoidable. A lot of it is a number made too late by somebody who was not going to own the outcome.
- Appraisal to sales: 2:1 minimum. This is the input. The other two are outputs.
Why it works
It converts a judgment call into a count. Nobody has to decide whether this particular customer seems like a trade. You appraise, and the ratio tells you whether the store is doing the work.
The reason most stores do not hold it is not disagreement. It is arithmetic. Two appraisals per sale, on top of everything else your used car manager owns, is more conversations than one desk can physically have in a day. So the rule gets applied to the customers who look like trades, which is exactly the filter that produced the 34%.
The rule is not hard to agree with. It is hard to staff.
Which is the honest reading of the whole trade-capture problem. It is a coverage constraint wearing a process costume.