How the figure is worked out

Worth reading before you trust a note.

The search is the weakest part

Your description is passed to Etsy's public listing search, and whatever comes back is the comparison set. Everything downstream is arithmetic; this step is the one that can be wrong. speckled stoneware mug finds something like your mug. mug finds every mug on Etsy and produces a wide, useless range with a confident sentence attached to it.

Then it is just quartiles

The prices are sorted. The lower quartile is the price a quarter of them sit below, the upper quartile the price three quarters sit below, and the midpoint is the middle one. The band you see drawn is the full range; the shaded part is the middle half. That middle half is what "the usual range" means everywhere on this site.

Three possible findings, and nothing else

Below the lower quartile is below the usual range. Above the upper quartile is above the usual range. Anything between is inside it. There is no score, no percentage, no five-star anything, because the underlying data does not support that much precision.

Under five listings it refuses

Quartiles over four numbers are theatre. If the search brings back fewer than five comparable listings the note says so and declines to rate. Between five and twelve it rates, and says out loud that the sample is thin.

What it re-checks, and what it does not

Every day it runs the search again and recomputes the band. It does not look at your listing's price again — it never stored one. The asking price is the number you typed, and it stays the number you typed until you change it. So when a finding improves, the price did not fall; the field around it moved.

What is thrown away

All of it, except five numbers. The listings that were compared are not stored, and neither is yesterday's band — today's overwrites it. There is no price history here to look at, by design and by Etsy's terms.