14 · Why it exists
Four objects, four bands, and what each one turned into. The figures are illustrative — they show how a band is read, not swaps that have happened.
The fourth is the interesting one. It is the case where the answer is genuinely uncertain, and showing it is worth more than four easy ones.
01
Boxed, with the paddle and the manual. Six years old, working.
A cast-iron skillet and a stovetop coffee pot
Both well seasoned, both in daily use by somebody who has two.
Neither side had to agree on a price. The bread maker's band covered both items, and the person with the skillet wanted the bread maker. That was the whole negotiation.
02
One outgrown and scuffed, one barely ridden. Both fold.
A box of building bricks and a wooden train set
About four kilograms of bricks, and track for a table.
A high-confidence band on both sides, because scooters and bricks are things a lot of people sell and the market for them is legible. The easiest kind of swap there is.
03
Aluminium, one dent in the down tube, wheel true.
A small guitar amplifier and a hard case
Fifteen watts, works, one scuffed corner.
The dent is why this is Medium rather than High. It is the kind of thing a photograph shows and a model can see, and it moves a frame's value more than its age does.
04the difficult one
No maker's mark that the photograph could read. Older than fifty years, possibly much older.
Nothing yet
It is still in the vault, and that is the right outcome.
This is the awkward one, and it is here on purpose. A band ten times wide at its top end is not a valuation you can trade against — at $25 it is a nice knife and at $260 it is a thing to take to somebody who knows. Low confidence is the system telling you it could not identify the maker, and the honest next step is a person, not a swap.
The awkward one
The knife is not a failure of the valuation. It is the valuation saying, accurately, that it could not read a maker’s mark and that the difference between the two readings is a factor of ten.
A single confident number there would have been worse in every way. You would have traded against it, and one of you would have been badly wrong.
A wide range with low confidence is the honest answer, not a failure.
What the confidence figure is measuring is on confidence, and how a band becomes a set of things you can have is on the band.
Try it on something with a mark on it, and something without. The difference between the two bands is the most interesting thing the product does.
The four above are illustrative, written to show how a band is read. They are not records of completed swaps, and nothing on this page is a claim that they happened.