How the numbers are made.
Every value on this site is built the same way, from recorded Australian sales, and every one can be checked against the sales it rests on. This is the whole method, with the figures it runs on today.
A sale counts when it has a price, a date and a car attached. Asking prices are recorded on the page they belong to and never counted as sales. A figure that cannot be tied to a date or a car is shown, labelled, and left out of the value.
Each of the 244 records holds the Australian results for one model and specification. Where the market prices a gearbox or a body differently and there is evidence to split it, it gets a record of its own, and a record that still pools two says so on its page.
Each sale is carried to the distance its record expects on a measured curve, so the further a car sits from that distance the less each extra kilometre moves the price. The rate is fitted from the record's own sales where they can support it.
Older sales are brought forward with a market index fitted on recorded sales, one per segment where a segment has ten or more observations behind it, and a pooled figure where it does not.
Options, colour and condition move the figure through the record's own ladder. When a judgement departs from the model, the call or report says by how much and why.
The values. Every recorded sale is predicted from the other sales of the same model only, with the answer taken away. Across 426 sales and 83 models the median error is 12.2 per cent, 41 per cent land inside ten per cent, and one in ten is out by more than 35 per cent. A value should be judged by that number.
The calls. A call is the harder test: a figure for one car, published before its auction closes and graded after. 21 have been graded. The median error is 9.8 per cent, 11 landed inside ten per cent, and the worst was 40.1 per cent out. They have run low more often than not, by 8.1 per cent on average, and that lean is being watched.
One number hides how sure it is, so every call carries a range sized by how much Australian evidence stands behind the car. The widths were measured on held-out sales so that about 85 results in a hundred should land inside them, and the range is lopsided where the evidence says values run high.
So far 10 of 19 graded ranges have held the hammer. That is short of the target, and it is the number this site most needs to improve.
CarQuant is run by Nick Markou in South Australia and registered under ABN 93 189 088 397. He reads and signs every report and publishes and grades the calls. A question about any figure on this site goes to him directly.
Send the advertisement and Nick prices that exact car: what to offer, what it is worth if it checks out, and when to walk away. $249, usually back within 48 hours.